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IB Math AA HL Revision Notes

Formulas, conditions, key connections and common exam traps across the five AA HL topics. Use it alongside the formula booklet and regular question practice.

Abdulhamid, IB Math tutor

Written by IB Math tutor Abdulhamid

IB Math Master · Updated

For the current AA HL syllabus, for exams up to November 2028.

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How to use these notes

Each topic is split into short sections. Every section keeps its formulas, conditions and diagrams together.

  • Connection (blue dot): links between formulas that the formula booklet does not state.
  • Exam note (gold diamond): short reminders and common traps.
  • Video: a link to my explanation of the topic.

Topic 1 Number and Algebra

Exponents and Logarithms

Exponent laws

NameFormulaCondition
Same base
am×an=am+naman=am−n
a>0, m,n∈ℚ
Powers of products
(am)n=amn(ab)n=anbn(ab)n=anbn
a,b>0
Zero and negative
a0=1a−n=1an
a≠0
Fractional
a1n=anamn=(an)m=amn
a>0
Standard form
a×10k
1≤a<10, k∈ℤ
  • Connection: a=a12 and 1a=a−12
  • Connection: Standard form products: multiply the a parts, add the powers of 10, then rescale to 1≤a<10.

Logarithms

NameFormulaCondition
Definition of a log
ax=b  ⟺  x=log⁡ab
a>0, b>0, a≠1
Inverses
log⁡aax=x=alog⁡ax
x>0 on the right
Base e
ax=exln⁡a
a>0
Product and quotient
log⁡a(xy)=log⁡ax+log⁡aylog⁡axy=log⁡ax−log⁡ay
x,y>0
Power
log⁡a(xm)=mlog⁡ax
x>0
Change of base
log⁡ba=log⁡calog⁡cb
a,b,c>0, b,c≠1
Base 10 and base e
log⁡x=log⁡10xln⁡x=log⁡ex
e≈2.718
  • Connection: log⁡a1=0 and log⁡aa=1
  • Connection: eln⁡x=x and ln⁡(ex)=x
  • Connection: log⁡a1x=−log⁡ax
  • Connection: log⁡ba=1log⁡ab
  • Connection: log⁡anx=1nlog⁡ax
  • Connection: ax=b ⇒ x=log⁡ab=ln⁡bln⁡a
  • Exam note: No law exists for log⁡(x+y), (log⁡x)2 or (log⁡x)(log⁡y). Leave them as they are.
  • Exam note: log⁡af(x) exists only when f(x)>0. Reject any answer that makes f(x)≤0.

Back to topics

Sequences and Series

Arithmetic and geometric sequences

ItemArithmetic common difference dGeometric common ratio r
nth term
un=u1+(n−1)d
un=u1rn−1
Sum of n terms
Sn=n2(2u1+(n−1)d)=n2(u1+un)

Sn=u1(rn−1)r−1=u1(1−rn)1−r, r≠1

Sum to infinity

S∞=u11−r, only when |r|<1

Finding d or r
u2−u1=u3−u2=⋯=d
u2u1=u3u2=⋯=r
  • Connection: For any sequence:
    S1=u1
    S2=u1+u2
    S3=u1+u2+u3
    un=Sn−Sn−1 for n≥2
  • Exam note: n counts terms, so n∈ℤ+.

Sigma notation

NameFormulaCondition
Sigma notation
∑i=1nui=u1+u2+⋯+un
i runs through whole numbers
  • Connection: Sums split: ∑(ai+bi)=∑ai+∑bi. Constants come out: ∑c ai=c∑ai.
  • Exam note: Check the first and last values of i.

Money: interest and depreciation

NameFormulaCondition
Compound interest
FV=PV×(1+r100k)kn

FV = future value, PV = present value, n = number of years, k = number of compounding periods per year, r% = nominal annual rate of interest

geometric, ratio 1+r100k per period
Depreciation
Vn=V0×(1−r100)n

V0 = starting value, Vn = value after n years, r% = annual rate of depreciation

geometric, ratio 1−r100 per year

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Counting and the Binomial Theorem

Counting

NameFormulaCondition
Factorial
n!=n(n−1)(n−2)⋯2×1
0!=1
Permutations
nPr=n!(n−r)!
order matters, 0≤r≤n
Combinations
nCr=n!r! (n−r)!
order does not matter
  • Connection: n!=n(n−1)(n−2)! for n≥2
  • Connection: nC0=nCn=1, nC1=n, nCr=nCn−r and nPn=n!

The binomial theorem

NameFormulaCondition
Binomial theorem
(a+b)n=∑r=0nnCr an−rbr=an+nC1 an−1b+⋯+nCr an−rbr+⋯+bn
n∈ℕ
General term
nCr an−rbr
the term in br, r=0,1,…,n
Pascal’s triangle
n=01
n=111
n=2121
n=31331
n=414641
n=515101051
row n gives nC0, nC1, …, nCn
  • Connection: (a+b)n has n+1 terms. In each term, the powers of a and b add up to n.
  • Exam note: A coefficient is the number only. A term includes the power of x.
  • Exam note: In (a−b)n, use −b as the second term. The signs alternate.
  • Exam note: Bracket the whole term: (2x)r=2rxr, not 2xr.

Extended binomial

NameFormulaCondition
Extended binomial
(a+b)n=an(1+ba)n=an(1+n(ba)+n(n−1)2!(ba)2+⋯ )
n∈ℚ, |ba|<1
  • Connection: (1−x)−1=1+x+x2+⋯ is the geometric series with r=x, valid for |x|<1.

Back to topics

Partial Fractions

Two linear factors

NameFormulaCondition
Two linear factors
px+q(ax+b)(cx+d)≡Aax+b+Bcx+d
the two factors are different
  • Connection: Clear the denominators: px+q≡A(cx+d)+B(ax+b). This holds for every x, so substitute the x that makes each factor zero.
  • Connection: In Topic 5: ∫Acx+d dx=Acln⁡|cx+d|+C
  • Exam note: Factorise the denominator fully first.
  • Exam note: The numerator must have lower degree than the denominator. If not, divide first.
  • Exam note: Watch the signs: 1a−x=−1x−a.

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Systems of Linear Equations

Up to three equations in three unknowns

Eliminate one unknown at a time.

ResultWhat you see after eliminating
Unique solution

Each unknown gets one value.

Infinitely many solutions

One equation becomes 0=0. It gives no new information. Let one unknown be any number λ, then write the other unknowns in terms of λ.

If two equations become 0=0, let two unknowns be λ and μ.

No solution

One equation becomes 0=c with c≠0, for example 0=5. This is impossible, so the system has no solution.

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Complex Numbers

Cartesian form

NameFormulaCondition
Cartesian form
z=a+biRe(z)=aIm(z)=bi2=−1
a,b∈ℝ
Conjugate and modulus
z∗=a−bi|z|=r=a2+b2
Argument
arg⁡z=θtan⁡θ=ba
a=rcos⁡θb=rsin⁡θ

check the quadrant

ReIm𝑎𝑏𝑟𝜃𝑧
Argand diagram
  • Connection: zz∗=|z|2
    z+z∗=2 Re(z)
    z−z∗=2i Im(z)
  • Connection: |z∗|=|z| and arg⁡z∗=−arg⁡z. Add 2π if this is outside the required range.
  • Connection: i1=i,i2=−1,i3=−i,i4=1
  • Exam note: a+bi=c+di  ⟺  a=c and b=d, for a,b,c,d∈ℝ. This gives two equations.
  • Exam note: Give arg⁡z in the range the question states, often −π<θ≤π or 0≤θ<2π.

Arguments on the axes

z lies on thezarg⁡zAll its arguments
positive real axis
a
0
0+2kπ
negative real axis
−a
π
π+2kπ
positive imaginary axis
bi
π2
π2+2kπ
negative imaginary axis
−bi
−π2
−π2+2kπ

Here a>0, b>0 and k∈ℤ. The arg⁡z column uses −π<θ≤π.

  • Exam note: Adding a multiple of 2π gives the same point. Give the argument in the range the question asks.
  • Exam note: Do not use tan⁡θ=ba here. On the imaginary axis a=0, and on the real axis it gives 0 for both 3 and −3. Sketch z, then read the angle.
  • Exam note: z=0 has no argument.
ReIm3arg=0−3arg=𝜋2𝑖arg=𝜋2−2𝑖arg=−𝜋2
Measure from the positive real axis.
Anticlockwise is positive. Clockwise is negative.

Polar and Euler forms

NameFormulaCondition
Polar and Euler forms
z=r(cos⁡θ+isin⁡θ)=reiθ=rcis⁡θ
Product
z1z2=r1r2cis⁡(θ1+θ2)
Quotient
z1z2=r1r2cis⁡(θ1−θ2)
z2≠0
  • Connection: |z1z2|=|z1||z2| and arg⁡(z1z2)=arg⁡z1+arg⁡z2
    |z1z2|=|z1||z2| and arg⁡(z1z2)=arg⁡z1−arg⁡z2
    Adjust arguments by 2π if needed.
  • Connection: z1+z2: vector addition (the diagonal of the parallelogram).
    z∗ is the reflection of z in the real axis.
  • Connection: Multiplying by i: rotate 90∘ anticlockwise about 0.
  • Connection: Multiplying by rcis⁡θ: enlarge by r and rotate by θ.
  • Connection: |z1−z2| is the distance between the points z1 and z2.
  • Connection: eiπ=−1 and |eiθ|=1
ReIm90∘𝑧𝑧∗𝑖𝑧
Reflection and 90∘ turn
ReIm𝜃|𝑧1−𝑧2|𝑧1𝑧2
z2=(rcis⁡θ) z1, |z2|=r|z1|

Powers and roots

NameFormulaCondition
De Moivre
[r(cos⁡θ+isin⁡θ)]n=rn(cos⁡nθ+isin⁡nθ)=rneinθ=rncis⁡nθ
n∈ℤ. For fractional powers, use the nth roots formula.
nth roots
zn=rcis⁡θ ⇒ z=r1ncis⁡(θ+2πkn)
n∈ℤ+, r>0
k=0,1,…,n−1
  • Connection: If |z|=1: zn+z−n=2cos⁡nθ
    zn−z−n=2isin⁡nθ
  • Connection: The roots of zn=w, w≠0, have equal modulus, and their arguments are 2πn apart. For n≥3 they form a regular n-gon centred at 0.
  • Connection: The n roots of zn=1 (the nth roots of unity) add to 0, for n≥2.
  • Exam note: Conjugate roots: if the coefficients are real and z is a root, then z∗ is a root.
  • Exam note: nth roots: list all n of them. Start at k=0, then put k=1,2,…,n−1. Keep every argument in the required range.
ReIm𝑟1𝑛2𝜋𝑛𝑧0𝑧1
Example with n=6: a regular hexagon

Back to topics

Proof

Deductive proof, contradiction and counterexample

NameFormulaCondition
Identity

The symbol ≡ means true for every value. In an equation, = holds for some values only.

LHS to RHS

Start from one side. Change it one step at a time until it becomes the other side.

LHS =⋯= RHS
Contradiction

Assume the statement is false. Reach something impossible. So the statement is true.

Counterexample

One case where the statement fails shows it is not always true.

  • Connection: Even numbers: 2m. Odd numbers: 2m±1. Consecutive integers: n, n+1. Here m,n∈ℤ.
  • Exam note: LHS to RHS: work on one side only. Do not rewrite the whole identity on every line.
  • Exam note: A counterexample is one specific value, with the check shown.

Proof by induction

NameFormulaCondition
Induction
  1. Show the statement is true for n=1 (or for the first value in the question, such as n=0 or n=2).
  2. Assume it is true for n=k.
  3. Prove it is true for n=k+1. This step always uses the assumption for n=k.
  4. Conclude: true for n=1, and true for n=k implies true for n=k+1, so true for all n∈ℤ+ by mathematical induction.
n∈ℤ+, or n from the first value
  • Exam note: Write “Assume true for n=k”, not “for all k”.
  • Exam note: In the n=k+1 step, show the line where you use the assumption for n=k.
  • Exam note: Write the full concluding sentence. Mark schemes usually give the final mark only when the earlier steps are there.

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Topic 2 Functions

Lines and Quadratics

Straight lines

NameFormulaCondition
Straight line
y=mx+cax+by+d=0y−y1=m(x−x1)
Gradient
m=y2−y1x2−x1
x1≠x2
Parallel lines
m1=m2
Perpendicular lines
m1×m2=−1m2=−1m1
m1≠0

The three forms of a quadratic

FormEquationWhat it shows
Standard
f(x)=ax2+bx+c
y-intercept (0,c)
axis of symmetry x=−b2a
vertex (−b2a, f(−b2a))
Factor
f(x)=a(x−p)(x−q)
x-intercepts (p,0), (q,0)
axis of symmetry x=p+q2
Vertex
f(x)=a(x−h)2+k
vertex (h,k)
axis of symmetry x=h
  • Connection: a>0: minimum at the vertex. a<0: maximum at the vertex.
𝑥𝑦axisofsymmetry𝑥=30,𝑐=0,5𝑝=1𝑞=5ℎ,𝑘=3,−4
f(x)=x2−6x+5=(x−1)(x−5)=(x−3)2−4

Roots and the discriminant

NameFormulaCondition
Quadratic formula
ax2+bx+c=0 ⇒ x=−b±b2−4ac2a
a≠0
Discriminant
Δ=b2−4ac
Δ>0

two distinct real roots: the graph crosses the x-axis twice

𝑥
Δ=0

two equal real roots: the graph touches the x-axis

𝑥
Δ<0

no real roots: the graph misses the x-axis

𝑥
Always positive

f(x)>0 for all x  ⟺  a>0 and Δ<0

𝑥
Always negative

f(x)<0 for all x  ⟺  a<0 and Δ<0

𝑥
  • Exam note: “Real roots” means Δ≥0. “Two distinct real roots” means Δ>0.

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Functions, Composites and Inverses

Functions and composites

NameFormulaCondition
Function

Each x in the domain gives exactly one y

Domain, range

Domain: the allowed inputs. Range: the outputs.

Composite
(f∘g)(x)=f(g(x))
apply g first
  • Connection: In general f∘g≠g∘f.

Inverse functions

NameFormulaCondition
Inverse

y=f(x): swap x and y, then make y the subject. f must be one-to-one.

Identity
(f∘f−1)(x)=(f−1∘f)(x)=x
Self-inverse

f−1(x)=f(x), so f(f(x))=x. Symmetric in y=x.

  • Connection: The graph of f−1 is the reflection of f in y=x.
  • Connection: Domain of f−1 = range of f
    Range of f−1 = domain of f
  • Exam note: f−1(x) is not 1f(x).
  • Exam note: Not one-to-one? Restrict the domain first, usually to one side of a turning point.
𝑥𝑦𝑦=𝑥𝑓𝑓−1
(1,2) on f and (2,1) on f−1

Odd and even functions

NameFormulaCondition
Odd
f(−x)=−f(x)

Half-turn symmetry about the origin

𝑥𝑦
Even
f(−x)=f(x)

Symmetric in the y-axis

𝑥𝑦

Back to topics

Graphs and Transformations

Transformations of y=f(x)

New graphTransformationPoint (x,y) moves to
y=f(x)+b
translation b units up
(x, y+b)
y=f(x)−b
translation b units down
(x, y−b)
y=f(x−a)
translation a units to the right
(x+a, y)
y=f(x+a)
translation a units to the left
(x−a, y)
y=−f(x)
reflection in the x-axis
(x, −y)
y=f(−x)
reflection in the y-axis
(−x, y)
y=pf(x)
vertical stretch, scale factor p
(x, py)
y=f(qx)
horizontal stretch, scale factor 1q
(xq, y)
y=f(ax+b)
translation b units to the left, then horizontal stretch, scale factor 1a
(x−ba, y)
  • Exam note: In this table a,b,p,q>0. So f(x)+b always moves up and f(x)−b always moves down.
  • Connection: Inside the bracket: changes x and works the opposite way to how it looks.
  • Connection: Outside the bracket: changes y and works the way it looks.
  • Connection: y=pf(x)+b: stretch first, then translate.
  • Exam note: Describe each transformation fully: type, direction and scale factor or distance.
𝑥𝑦+2𝑥𝑦÷2
Dashed y=x2. Left: y=(x−2)2 moves right 2. Right: y=(2x)2 divides each x by 2.

Sketching

  • Exam note: Label key features on a sketch: intercepts, turning points, asymptotes and domain end points.
  • Exam note: Papers 2 and 3: find intersections, zeros and turning points with the GDC.

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Special Function Graphs

Each graph is drawn from f(x)=x2−4x+3, shown dashed. Gold lines are asymptotes.

y=|f(x)|

On y=f(x)On y=|f(x)|
Part on or above the x-axis, f(x)≥0

stays the same

Part below the x-axis, f(x)<0

reflected in the x-axis

Graph

on or above the x-axis: y≥0

𝑥𝑦

y=f(|x|)

On y=f(x)On y=f(|x|)
Part for x≥0

stays the same

Part for x<0

removed. It is replaced by the reflection of the x≥0 part in the y-axis.

Symmetry

symmetric in the y-axis: an even function

𝑥𝑦

y=1f(x)

On y=f(x)On y=1f(x)
Zero at x=a, f(a)=0

vertical asymptote x=a

Vertical asymptote x=a

1f(x)→0 as x→a

hole at (a,0): still undefined at x=a

f(x)→±∞ as x→±∞

horizontal asymptote y=0

Horizontal asymptote y=k, k≠0

horizontal asymptote y=1k

Positive or negative

same sign

Points where f(x)=1 or f(x)=−1

stay fixed

Increasing

decreasing

Decreasing

increasing

Maximum point, not on the x-axis

minimum point, same x

Minimum point, not on the x-axis

maximum point, same x

𝑥𝑦

y=[f(x)]2

On y=f(x)On y=[f(x)]2
Zero at x=a

touches the x-axis at x=a

Negative values

become positive, so y≥0

Values with |f(x)|>1

move away from the x-axis

Values with |f(x)|<1

move closer to the x-axis

Points where f(x)=0 or f(x)=1

stay fixed

Points where f(x)=−1

move to y=1

𝑥𝑦

Back to topics

Rational Functions

Types and their asymptotes

Typef(x)AsymptotesExample
Reciprocal
1x

vertical x=0

horizontal y=0

self-inverse: f−1(x)=1x

Linear over linear
ax+bcx+d

vertical: where the denominator cx+d=0

horizontal y=ac

𝑥𝑦
y=2x+1x−1
Linear over quadratic
ax+bcx2+dx+e

vertical: where the denominator cx2+dx+e=0

horizontal y=0

𝑥𝑦
y=x+1x2−4
Quadratic over linear
ax2+bx+cdx+e

vertical: where the denominator dx+e=0

oblique y=mx+k

𝑥𝑦
y=x2+1x−1

Finding asymptotes and intercepts

  • Connection: Vertical asymptote: the x that makes the denominator 0 (numerator ≠0).
  • Connection: x-intercept: put y=0. y-intercept: put x=0.
  • Connection: Horizontal asymptote, compare degrees:
    top < bottom: y=0
    top = bottom: y= ratio of leading coefficients
  • Connection: Oblique asymptote when the top degree is one more: divide to get f(x)=mx+k+Rdx+e, so y=mx+k.
  • Exam note: Write asymptotes as equations.
  • Exam note: A graph can cross a horizontal or oblique asymptote. It never crosses a vertical one.

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Exponential and Logarithmic Functions

The two graphs

NameFormulaCondition
Exponential
f(x)=axf(x)=exa>0, a≠1
domain ℝ, range y>0
asymptote y=0, through (0,1)
Logarithmic
f(x)=log⁡axf(x)=ln⁡x
domain x>0, range ℝ
asymptote x=0, through (1,0)
  • Connection: ax and log⁡ax are inverses: reflections in y=x. The same holds for ex and ln⁡x.
𝑥𝑦𝑦=𝑥𝑦=𝑒𝑥𝑦=ln𝑥11

Changing the graphs

  • Connection: a>1: increasing. 0<a<1: decreasing.
  • Connection: a−x=(1a)x: the reflection of ax in the y-axis
  • Connection: y=Aekx+c: asymptote y=c. k>0: growth. k<0: decay.
  • Connection: log⁡ag(x) needs g(x)>0. Its vertical asymptote is where g(x)=0.
  • Exam note: Translations move the asymptote too.
  • Exam note: In y=Aekt+c, the value at t=0 is A+c, not A.

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Solving Equations and Inequalities

Using graphs

NameFormulaCondition
Graphical solution

Solutions of f(x)=g(x) are the x-coordinates where the graphs meet

f(x)>g(x)

The x-values where the graph of f is above g

  • Connection: Number of solutions = number of intersection points

Quadratic inequalities

NameFormulaCondition
Roots α<β, a>0

ax2+bx+c>0  ⟺  x<α or x>β

ax2+bx+c<0  ⟺  α<x<β

  • Exam note: Sketch the graph, then read off where it is above or below the x-axis.
  • Exam note: Multiplying or dividing by a negative number reverses the inequality.
𝑥𝛼𝛽++−

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Polynomials

Factor and remainder theorems

NameFormulaCondition
Polynomial
P(x)=anxn+an−1xn−1+⋯+a1x+a0
an≠0, degree n
Factor theorem

P(k)=0  ⟺  (x−k) is a factor

Remainder theorem

P(x)÷(x−k) leaves remainder P(k)

  • Connection: Divisor (ax−b): remainder P(ba)

Sum and product of roots

NameFormulaCondition
Sum of roots
−an−1an
for ∑r=0narxr=0
Product of roots
(−1)na0an
  • Connection: Quadratic ax2+bx+c=0: α+β=−ba and αβ=ca
  • Exam note: Write the equation as … = 0 before using the sum and product formulas.
  • Exam note: The sum and product include repeated and complex roots.

Shape of the graph

NameFormulaCondition
Single root

The graph crosses the x-axis.

Double root

(x−a)2 is a factor, so x=a is a root twice. The graph touches the x-axis at x=a and turns there.

  • Connection: Degree n: at most n real roots and at most n−1 turning points
  • Connection: For large |x|, P(x) behaves like anxn.

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Topic 3 Geometry and Trigonometry

3D Geometry and Triangles

Points in 3D

NameFormulaCondition
Distance
d=(x1−x2)2+(y1−y2)2+(z1−z2)2
Midpoint
(x1+x22, y1+y22, z1+z22)

Solids

NameFormulaCondition
Right pyramid
V=13Ah, A = area of base, h = height
Right cone
V=13πr2h curved surface A=πrl
total surface =πrl+πr2 l2=r2+h2, l = slant height
Sphere
V=43πr3A=4πr2
Hemisphere
V=23πr3 curved surface 2πr2
ℎ𝑟𝑙

Right-angled triangles

NameFormulaCondition
Ratios
sin⁡θ=opphypcos⁡θ=adjhyptan⁡θ=oppadj
Pythagoras
a2+b2=c2, c = hypotenuse
𝜃adjacentoppositehypotenuse
Opposite and adjacent are named from θ.

Angles of elevation and depression

  • Exam note: Angles of elevation and depression are measured from the horizontal.
  • Connection: The angle of elevation of B from A equals the angle of depression of A from B.
horizontal𝐴𝐵elevationdepression
Both angles are measured from the horizontal.

Any triangle

NameFormulaCondition
Sine rule
asin⁡A=bsin⁡B=csin⁡C
Cosine rule
c2=a2+b2−2abcos⁡C
cos⁡C=a2+b2−c22ab
Area
A=12absin⁡C
𝐴𝐵𝐶𝑐𝑎𝑏
Side a is opposite angle A, and so on.
Use the sine rule when you knowUse the cosine rule when you know
  • two angles and one side
  • two sides and an angle not between them
    (this can be the ambiguous case)
  • two sides and the angle between them
  • all three sides
  • Exam note: Set the GDC to degrees or radians to match the question.

The ambiguous case of the sine rule

  • Exam note: It happens only when you know two sides and an angle not between them, and you use the sine rule to find an angle.
  • Exam note: sin⁡θ=k gives two angles: θ and 180∘−θ. Check both. Keep 180∘−θ only if the angles of the triangle still add up to 180∘ with every angle positive.
𝑐𝑎𝑎𝐴𝐶1𝐶2𝐵
Ambiguous case only: two triangles fit the same A, c and a.

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Radians and the Unit Circle

Radians, arcs and sectors

NameFormulaCondition
Radians
π radians=180∘
Arc length
l=rθ
θ in radians
Sector area
A=12r2θ
θ in radians
𝑟𝑙=𝑟𝜃𝜃𝐴
  • Exam note: Arc length and sector area need θ in radians.

The unit circle and exact values

NameFormulaCondition
Unit circle
cos⁡θ=x-coordinate
sin⁡θ=y-coordinate
Tan
tan⁡θ=sin⁡θcos⁡θ, cos⁡θ≠0
θ0π6π4π3π2
sin⁡θ
0
12
22
32
1
cos⁡θ
1
32
22
12
0
tan⁡θ
0
33
1
3

undefined

The full unit circle is on the next page.

The unit circle

𝑥𝑦𝑂00∘1,0𝜋630∘32,12𝜋445∘22,22𝜋360∘12,32𝜋290∘0,12𝜋3120∘−12,323𝜋4135∘−22,225𝜋6150∘−32,12𝜋180∘−1,07𝜋6210∘−32,−125𝜋4225∘−22,−224𝜋3240∘−12,−323𝜋2270∘0,−15𝜋3300∘12,−327𝜋4315∘22,−2211𝜋6330∘32,−12allpositivesinpositivetanpositivecospositive
Each point is (cos⁡θ, sin⁡θ). Angles are measured anticlockwise from the positive x-axis. tan⁡θ=yx.

Example: θ=30∘=π6

The point on the unit circle at 30∘ is (32, 12).

cos⁡30∘=x-coordinate =32

sin⁡30∘=y-coordinate =12

tan⁡30∘=yx=1232=13=33

𝑥𝑦1cos30∘=32sin30∘=1230∘32,12

Symmetries from the unit circle

sincostan
sin⁡(π−θ)=sin⁡θ
cos⁡(π−θ)=−cos⁡θ
tan⁡(π−θ)=−tan⁡θ
sin⁡(−θ)=−sin⁡θ
cos⁡(−θ)=cos⁡θ
tan⁡(−θ)=−tan⁡θ
sin⁡(π+θ)=−sin⁡θ
cos⁡(π+θ)=−cos⁡θ
tan⁡(π+θ)=tan⁡θ
sin⁡(π2−θ)=cos⁡θ
cos⁡(π2−θ)=sin⁡θ
  • Exam note: Exact values of multiples: find the reference angle, then the sign from the quadrant.

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Trigonometric Identities

Reciprocal ratios and Pythagorean identities

NameFormulaCondition
Reciprocal ratios
sec⁡θ=1cos⁡θcosec⁡θ=1sin⁡θcot⁡θ=1tan⁡θ=cos⁡θsin⁡θ
Pythagorean
cos⁡2θ+sin⁡2θ=1
1+tan⁡2θ=sec⁡2θ
1+cot⁡2θ=cosec⁡2θ
  • Connection: Divide cos⁡2θ+sin⁡2θ=1 by cos⁡2θ to get 1+tan⁡2θ=sec⁡2θ, or by sin⁡2θ to get 1+cot⁡2θ=cosec⁡2θ.

Compound and double angles

NameFormulaCondition
Compound angle
sin⁡(A±B)=sin⁡Acos⁡B±cos⁡Asin⁡B
cos⁡(A±B)=cos⁡Acos⁡B∓sin⁡Asin⁡B
tan⁡(A±B)=tan⁡A±tan⁡B1∓tan⁡Atan⁡B
Double angle
sin⁡2θ=2sin⁡θcos⁡θ
cos⁡2θ=cos⁡2θ−sin⁡2θ=2cos⁡2θ−1=1−2sin⁡2θ
tan⁡2θ=2tan⁡θ1−tan⁡2θ
  • Connection: Put B=A in the compound angle formulas to get the double angle formulas.
  • Connection: cos⁡2θ=1+cos⁡2θ2 and sin⁡2θ=1−cos⁡2θ2
  • Exam note: sin⁡2θ≠2sin⁡θ.
  • Exam note: Pick the cos⁡2θ form that matches the rest of the equation: all sin or all cos.

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Trigonometric Functions

The three graphs

NameFormulaCondition
sin⁡x, cos⁡x
period 2π range −1≤y≤1
sin is odd (blue). cos is even (dark).
𝑥𝑦1−1𝜋2𝜋
tan⁡x
period π
asymptotes x=π2+kπ, k∈ℤ
𝑥

Transformed sine and cosine

NameFormulaCondition
Functions
f(x)=asin⁡(b(x−c))+df(x)=acos⁡(b(x−c))+d
b>0
FeatureFrom the functionFrom the graph
Amplitude
|a|
max−min2
Period
radians: 2πb
degrees: 360∘b

from a maximum to the next maximum, or from a minimum to the next minimum

then b=2πperiod or b=360∘period

Principal axis
y=d
y=max+min2
Maximum, minimum
d+|a|, d−|a|

the highest and lowest y-values

Horizontal shift

c to the right
(c<0: to the left)

sine with a>0: the x where the graph crosses y=d going up
cosine with a>0: the x of a maximum point

  • Connection: Example: amplitude 1.5, period 2π2=π, principal axis y=2, shift π4 to the right, maximum 2+1.5=3.5, minimum 2−1.5=0.5.
𝑥𝑦𝑦=2𝜋4𝜋2𝜋3𝜋2𝑐=𝜋41.5min=2−1.5=0.5period=𝜋max=3.5
f(x)=1.5sin⁡(2(x−π4))+2: a=1.5, b=2, c=π4, d=2

Inverse trig functions

NameFormulaCondition
arcsin⁡x
domain −1≤x≤1
range −π2≤y≤π2
𝑥𝜋2−𝜋2
arccos⁡x
domain −1≤x≤1
range 0≤y≤π
𝑥𝜋
arctan⁡x
domain ℝ
range −π2<y<π2
𝑥𝜋2−𝜋2

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Vectors

Vector basics

NameFormulaCondition
Components
𝐯=v1𝐢+v2𝐣+v3𝐤=(v1v2v3)
Magnitude
|𝐯|=v12+v22+v32
Unit vector
𝐯|𝐯|
Displacement
AB→=𝐛−𝐚
  • Connection: Parallel: 𝐰=k𝐯. Two vectors are parallel when one is a multiple of the other.

Scalar product

NameFormulaCondition
Scalar product
𝐯⋅𝐰=v1w1+v2w2+v3w3=|𝐯||𝐰|cos⁡θ
θ = angle between 𝐯 and 𝐰
Angle between vectors
cos⁡θ=v1w1+v2w2+v3w3|𝐯||𝐰|
  • Connection: Perpendicular: 𝐯⋅𝐰=0
  • Connection: 𝐯⋅𝐯=|𝐯|2 and 𝐰⋅𝐯=𝐯⋅𝐰
  • Exam note: 𝐯⋅𝐰 is a number.
  • Exam note: For the angle at a vertex, both vectors must start at that vertex.
𝐯𝐰𝜃
θ is between the two vectors, both starting at the same point.

Vector product

NameFormulaCondition
Vector product
𝐯×𝐰=(v2w3−v3w2v3w1−v1w3v1w2−v2w1)
|𝐯×𝐰|=|𝐯||𝐰|sin⁡θ
Area of parallelogram
A=|𝐯×𝐰|, 𝐯, 𝐰 adjacent sides
  • Connection: 𝐯×𝐰 is perpendicular to both 𝐯 and 𝐰.
  • Connection: 𝐰×𝐯=−(𝐯×𝐰)
  • Connection: Parallel: 𝐯×𝐰=𝟎
  • Connection: Area of triangle =12|𝐯×𝐰|
  • Exam note: 𝐯×𝐰 is a vector.
𝐯𝐰𝜃12|𝐯×𝐰|
Parallelogram area |𝐯×𝐰|. Triangle: half of it.

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Lines and Planes

Lines

NameFormulaCondition
Vector form
𝐫=𝐚+λ𝐛
(xyz)=(x0y0z0)+λ(lmn)

𝐚=(x0y0z0): a point on the line

𝐛=(lmn): direction vector

Parametric form
x=x0+λl,y=y0+λm,z=z0+λn
Cartesian form
x−x0l=y−y0m=z−z0n
Parallel

Directions are parallel. Coincident if they also share a point.

Intersecting

One solution for λ and μ in all three components

Skew

Not parallel and no common point (3D only): one line passes over the other

  • Connection: Kinematics 𝐫=𝐚+t𝐯: 𝐚 = initial position, 𝐯 = velocity, speed = |𝐯|
  • Exam note: Intersecting lines: solve two components, then check the third.

Planes

NameFormulaCondition
Vector form
𝐫=𝐚+λ𝐛+μ𝐜
(xyz)=(x0y0z0)+λ(b1b2b3)+μ(c1c2c3)
𝐚: a point on the plane
𝐛, 𝐜: two directions in the plane, not parallel
Normal form
𝐫⋅𝐧=𝐚⋅𝐧
(xyz)⋅(n1n2n3)=(x0y0z0)⋅(n1n2n3)
𝐧=(n1n2n3): the normal vector
Cartesian form
ax+by+cz=d
𝐧=(abc)
  • Connection: Normal to 𝐫=𝐚+λ𝐛+μ𝐜: 𝐧=𝐛×𝐜
  • Connection: Line meets plane: substitute the line into the plane and solve for λ.
    No solution: line parallel to plane
    True for all λ: line lies in the plane
  • Connection: Two non-parallel planes meet in a line with direction 𝐧1×𝐧2.
  • Connection: Three planes: solve as a system (Topic 1).

Angles

NameFormulaCondition
Two lines
cos⁡θ=|𝐛1⋅𝐛2||𝐛1||𝐛2|, directions
Line and plane
sin⁡θ=|𝐛⋅𝐧||𝐛||𝐧|, direction and normal
Two planes
cos⁡θ=|𝐧1⋅𝐧2||𝐧1||𝐧2|, normals
  • Exam note: Each formula gives the acute angle θ: the modulus makes the right side positive.
  • Exam note: Two lines or two planes: without the modulus you may get the obtuse angle. The acute angle is then 180∘−θ. Line and plane: always use |𝐛⋅𝐧|.
  • Exam note: Line and plane: use sin, because 𝐧 is at 90∘ to the plane.
𝐧line,𝐛projection𝜃90∘−𝜃

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Topic 4 Statistics and Probability

Data and Statistics

Mean and spread

NameFormulaCondition
Mean
x¯=∑fixin
n=∑fi
Variance
σ2=∑fi(xi−μ)2n=∑fixi2n−μ2
Standard deviation
σ=∑fi(xi−μ)2n
Grouped data

use mid-interval values as xi

gives an estimate
Change to every valueMeanStandard deviation σVariance σ2IQR
Add k to every value
mean+k
unchanged
unchanged
unchanged
Subtract k from every value
mean−k
unchanged
unchanged
unchanged
Multiply every value by k
mean×k
σ×|k|
σ2×k2
IQR×|k|
Divide every value by k, k≠0
mean÷k
σ÷|k|
σ2÷k2
IQR÷|k|
  • Connection: Adding or subtracting k moves every value by the same amount, so the spread does not change.
  • Connection: Example: 2, 4, 6 has mean 4. Add 10 to every value: 12, 14, 16, mean 14, same spread. Multiply every value by 3: 6, 12, 18, mean 12, and σ is 3 times larger.
  • Exam note: Use σx from the GDC, not sx.

Quartiles, outliers and box plots

NameFormulaCondition
Interquartile range
IQR=Q3−Q1
Outlier

below Q1−1.5×IQR or above Q3+1.5×IQR

Cumulative frequency

read across at n4 for Q1, n2 for the median, 3n4 for Q3

percentile p: at p% of n
0123456789101112131415161718min=1𝑄1=4median=8𝑄3=13max=16IQR=13−4=9
Data: 1, 3, 4, 6, 7, 8, 10, 11, 13, 14, 16. Read each value from the scale.

Sampling and data

NameFormulaCondition
Population, sample

The population is the whole group being studied. A sample is part of it.

Simple random sample

Every possible sample of that size is equally likely to be chosen.

Bias, reliability

A biased sample does not represent the population. Check that the source of the data is reliable.

Frequency distribution

A table of values or classes with their frequencies. A histogram shows it as bars with no gaps.

Mode, modal class

The value with the highest frequency. For grouped data: the class with the highest frequency.

  • Connection: Sampling methods: simple random, systematic, stratified, quota, convenience
  • Exam note: Discrete data is counted. Continuous data is measured.

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Correlation and Regression

Correlation

NameFormulaCondition
Pearson’s r
−1≤r≤1
from the GDC
  • Connection: r close to ±1: strong linear correlation. r close to 0: weak or no linear correlation. The sign of r gives the direction.
  • Connection: Scatter diagram: plot each pair (x,y) as a point. A line of best fit drawn by eye passes through the mean point (x¯,y¯).
  • Exam note: Correlation does not mean causation.

Regression lines

NameFormulaCondition
y on x

y=ax+b: predicts y from x

x on y

x=cy+d: predicts x from y

  • Connection: For each increase of 1 in x, y changes by a.
    When x=0, y=b.
  • Connection: Both lines pass through (x¯,y¯).
  • Exam note: The y on x line predicts y from x only. Using it to predict x from y is not reliable: use the x on y line.
  • Exam note: Interpolation is reliable when the correlation is strong (r is close to ±1). Extrapolation is not reliable.
𝑥𝑦𝑦on𝑥𝑥on𝑦𝑥̄𝑦̄
Both lines pass through (x¯,y¯)

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Probability

Basic rules

NameFormulaCondition
Probability of A

P(A)=n(A)n(U), equally likely outcomes

Complementary events
P(A)+P(A′)=1
Combined events
P(A∪B)=P(A)+P(B)−P(A∩B)
Mutually exclusive
P(A∩B)=0
so P(A∪B)=P(A)+P(B)
Expected number
np for n trials with probability p
𝐴𝐵𝑈𝐴∩𝐵:inboth𝐴and𝐵𝐴𝐵𝑈𝐴∪𝐵:in𝐴or𝐵orboth
P(A)+P(B) counts A∩B twice, so subtract P(A∩B) once.

Conditional probability and independence

NameFormulaCondition
Conditional
P(A∣B)=P(A∩B)P(B)
Independent
P(A∩B)=P(A) P(B)
  • Connection: Independent   ⟺  P(A∣B)=P(A)=P(A∣B′)
  • Connection: P(A∩B)=P(A∣B) P(B)=P(B∣A) P(A)
  • Exam note: “Given that” means conditional: divide by the probability of the given event.

Tree diagrams and Bayes’ theorem

NameFormulaCondition
Bayes’ theorem
P(B∣A)=P(B) P(A∣B)P(B) P(A∣B)+P(B′) P(A∣B′)
Three events
P(Bi∣A)=P(Bi) P(A∣Bi)P(B1) P(A∣B1)+P(B2) P(A∣B2)+P(B3) P(A∣B3)
  • Connection: Tree diagram: multiply along branches and add the end results.
  • Connection: Bayes is the tree read backwards: the branch you want over all branches that give A.
  • Exam note: Without replacement, the second-stage probabilities change.
0.010.990.950.050.080.92𝐵𝐵𝐴0.01×0.95𝐴𝐴0.99×0.08𝐴
P(B∣A)=0.01×0.950.01×0.95+0.99×0.08

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Discrete Distributions

Discrete random variables

NameFormulaCondition
Probability distribution
∑P(X=x)=1
0≤P(X=x)≤1
Expected value
E(X)=μ=∑x P(X=x)
Variance
Var⁡(X)=∑(x−μ)2 P(X=x)=∑x2 P(X=x)−μ2
Var⁡(X)=E(X2)−[E(X)]2
  • Connection: E(aX+b)=a E(X)+b and Var⁡(aX+b)=a2Var⁡(X)
  • Connection: Standard deviation σ=Var⁡(X)
  • Connection: Fair game: E(gain)=0

Binomial distribution

NameFormulaCondition
Binomial
X∼B(n,p) ⇒ P(X=x)=nCx px(1−p)n−x
x=0,1,…,n
Mean and variance
E(X)=npVar⁡(X)=np(1−p)
  • Connection: Conditions: fixed n, two outcomes (success and failure), constant p, independent trials
  • Connection: P(X≥k)=1−P(X≤k−1)
    P(X>k)=1−P(X≤k)
  • Exam note: GDC: binomial pdf for P(X=x) and binomial cdf for P(X≤x).
  • Exam note: “At least”, “more than” and “fewer than”: rewrite with ≤ before using the cdf.
0123456P𝑋≤2P𝑋≥3
X∼B(6,0.4): P(X≥3)=1−P(X≤2)

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The Normal Distribution

The normal curve

NameFormulaCondition
Normal
X∼N(μ,σ2)
σ2= variance
Properties

symmetric about μ, mean = median = mode, total area 1

  • Connection: Normal probabilities such as P(a<X<b): use the normal cdf on the GDC with the lower bound, the upper bound, μ and σ.
  • Exam note: N(μ,σ2) gives the variance. Take the square root for σ.

The empirical rule

𝜇−3𝜎20𝜇−2𝜎30𝜇−𝜎40𝜇50𝜇+𝜎60𝜇+2𝜎70𝜇+3𝜎8034.13%34.13%13.59%13.59%2.14%2.14%0.13%0.13%about68%about95%about99.7%
Blue numbers: the example X∼N(50,102), so μ=50 and σ=10. Each percentage is the area to 2 decimal places.

Using symmetry: an example

  • Connection: X∼N(50,102)
  • Connection: P(X<50)=0.5
  • Connection: P(X<40)=P(X>60), because 40 and 60 are both 10 from the mean.
  • Connection: P(X=45)=0, so P(X<45)=P(X≤45).
405060P𝑋<40P𝑋>60
X∼N(50,102): the two gold areas are equal.

Standardising and the inverse normal

NameFormulaCondition
Standardised variable
z=x−μσ
Z∼N(0,1)
  • Connection: μ or σ unknown, with a given probability such as P(X<x)=p:
    1. Standardise with the z formula: P(X<x)=P(Z<x−μσ)=p, where Z∼N(0,1).
    2. Use the inverse normal on N(0,1), with mean 0 and standard deviation 1, to find the z-value with P(Z<z)=p.
    3. Set x−μσ=z and solve for the unknown.
  • Connection: Example: X∼N(μ,42) and P(X<30)=0.9. Inverse normal: z=1.2816. So 30−μ4=1.2816, giving μ=24.87 (2 d.p.).
  • Connection: Both μ and σ unknown: two probabilities are given. Do steps 1 to 3 for each one. This gives two equations in μ and σ. Solve them together.
  • Exam note: Inverse normal: check which tail the GDC uses.

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Continuous Random Variables

Probability density functions

NameFormulaCondition
pdf conditions

f(x)≥0 and ∫−∞∞f(x) dx=1

Probability
P(a≤X≤b)=∫abf(x) dx
  • Connection: Outside the given domain, f(x)=0, so integrate over the domain only.
  • Exam note: Piecewise pdf: integrate each piece over its own interval.
𝑥𝑓𝑥1234P1≤𝑋≤3
f(x)=332x(4−x), 0≤x≤4: probability is area

Mean, variance, mode and median

NameFormulaCondition
Expected value
E(X)=μ=∫−∞∞x f(x) dx
Variance
Var⁡(X)=E(X−μ)2=E(X2)−[E(X)]2
Var⁡(X)=∫−∞∞(x−μ)2f(x) dx=∫−∞∞x2f(x) dx−μ2
Mode

the x where f(x) is greatest

Median m
∫−∞mf(x) dx=12
  • Connection: E(aX+b)=a E(X)+b and Var⁡(aX+b)=a2Var⁡(X), as for discrete X
  • Connection: E(g(X))=∫−∞∞g(x) f(x) dx
  • Exam note: The mode can be at an end point of the domain, not only where f′(x)=0.
  • Exam note: Check the median lies inside the domain.

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Topic 5 Calculus

Limits and First Principles

Limits and continuity

NameFormulaCondition
Limit
lim⁡x→af(x): the value f(x) approaches as x→a
  • Connection: Continuous at a: lim⁡x→af(x)=f(a)
  • Connection: Differentiable at a means continuous at a. The reverse is not necessarily true: |x| is continuous at x=0 but not differentiable there.
  • Connection: lim⁡x→0sin⁡xx=1 (x in radians)

First principles

NameFormulaCondition
Derivative
y=f(x) ⇒ dydx=f′(x)=lim⁡h→0f(x+h)−f(x)h

the gradient function and the rate of change of y with respect to x

Higher derivatives
f″(x)=d2ydx2f(n)(x)=dnydxn
  • Exam note: Expand f(x+h), cancel h, then let h→0.
𝑥𝑦𝑥𝑥+ℎchordtangent
As h→0 the chord turns into the tangent.

L’Hôpital’s rule

NameFormulaCondition
L’Hôpital’s rule
lim⁡x→af(x)g(x)=lim⁡x→af′(x)g′(x)
form 00 or ∞∞
also as x→∞
  • Connection: Still 00 or ∞∞ after one step: use l’Hôpital again.
  • Exam note: Check the form is 00 or ∞∞ before using l’Hôpital.
  • Exam note: Differentiate the top and bottom separately. It is not the quotient rule.

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Differentiation Rules

Standard derivatives

f(x)f′(x)
xn
nxn−1
sin⁡x
cos⁡x
cos⁡x
−sin⁡x
tan⁡x
sec⁡2x
ex
ex
ln⁡x
1x
f(x)f′(x)
sec⁡x
sec⁡xtan⁡x
cosec⁡x
−cosec⁡xcot⁡x
cot⁡x
−cosec⁡2x
ax
ax(ln⁡a)
log⁡ax
1xln⁡a
arcsin⁡x
11−x2
arccos⁡x
−11−x2
arctan⁡x
11+x2
  • Exam note: Trig derivatives need x in radians.

Chain, product and quotient rules

NameFormulaCondition
Chain rule
y=g(u), where u=f(x) ⇒ dydx=dydu×dudx
Product rule
y=uv ⇒ dydx=udvdx+vdudx
Quotient rule
y=uv ⇒ dydx=vdudx−udvdxv2
  • Connection: ddxf(ax+b)=a f′(ax+b)
  • Connection: ddxeg(x)=g′(x) eg(x) and ddxln⁡g(x)=g′(x)g(x)
  • Connection: ddx[g(x)]n=n[g(x)]n−1g′(x)
  • Exam note: Simplify first: split fractions and use log laws before differentiating.

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Using Derivatives

Shape of a graph

IfThen

f′(x)>0

f is increasing

f′(x)<0

f is decreasing

f′(a)=0

stationary point at x=a

f′(a)=0 and f″(a)<0

local maximum at x=a

f′(a)=0 and f″(a)>0

local minimum at x=a

f′(a)=0 and f″(a)=0

the test fails: check the sign of f′ on each side of a

f′(a)=0, f″(a)=0 and f″ changes sign at a

horizontal (stationary) point of inflection at x=a

f″(x)>0

concave up

f″(x)<0

concave down

f″(a)=0 and f″ changes sign at a

point of inflection at x=a

  • Connection: Second derivative test: first solve f′(x)=0 to find the stationary point x=a. Then test the sign of f″(a).
  • Connection: f turns where f′=0 and f′ changes sign. f has an inflection where f′ turns.
  • Connection: Horizontal (stationary) inflection: the tangent is horizontal, f′=0 there. Non-stationary inflection: f′≠0 there.
  • Exam note: f″(a)=0 alone does not prove an inflection. Check the sign change.
𝑥𝑓𝑥𝑎=−1:𝑓𝑎=0𝑓𝑎=−6<0:max𝑎=1:𝑓𝑎=0𝑓𝑎=6>0:mininflection𝑥𝑓𝑥
f(x)=x3−3x. Step 1: f′(x)=3x2−3=0 gives the turning points a=−1 and a=1.
Step 2: test each one with f″(x)=6x. f has an inflection where f′ turns.
𝑥𝑦inflection1,2𝑓1=0concavedown𝑓𝑥<0concaveup𝑓𝑥>0maxmin
f(x)=x3−3x2+4, f″(x)=6x−6: concave down for x<1, concave up for x>1, inflection at (1,2).
𝑥𝑦𝑓0=0,𝑓0=0𝑓changessign
f(x)=x3: a horizontal point of inflection at the origin. The tangent there is horizontal.

Sketching the first and second derivatives

Graph of fGraph of f′Graph of f″

increasing

above the x-axis
(f′>0)

decreasing

below the x-axis
(f′<0)

max or min

crosses the x-axis
(f′=0)

point of inflection

max or min

crosses the x-axis
(f″=0)

concave up

increasing

above the x-axis
(f″>0)

concave down

decreasing

below the x-axis
(f″<0)

  • Connection: f′ touches the x-axis without crossing: a horizontal point of inflection of f.
  • Exam note: Mark the x-values of the key points of f first. Then sketch f′ through them.
012𝑥𝑓maxmininflection𝑥𝑓minof𝑓𝑥𝑓
f(x)=x3−3x2+2
Max at x=0 and min at x=2: f′ crosses the axis.
Inflection at x=1: f′ has its min and f″ crosses the axis.

Tangents and normals

  • Connection: Tangent at x=a: find the point (a,f(a)) and the gradient m=f′(a). Put them into the equation of a straight line.
  • Connection: Normal at x=a: the same point, with gradient −1m, because the normal is perpendicular to the tangent. If m=0, the normal is x=a.

Implicit differentiation and related rates

NameFormulaCondition
Implicit
ddx(yn)=nyn−1dydx
Related rates
dydt=dydx×dxdt
  • Connection: Implicit products: ddx(x2y)=2xy+x2dydx
  • Exam note: Related rates: a decreasing quantity has a negative rate.

Optimisation

  • Connection: Write the quantity in one variable, set the derivative to 0, then confirm max or min.
  • Exam note: Check the end points of the domain too.

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Integration

Standard integrals

∫xn dx=xn+1n+1+C,n≠−1
∫1x dx=ln⁡|x|+C
∫sin⁡x dx=−cos⁡x+C
∫cos⁡x dx=sin⁡x+C
∫ex dx=ex+C
∫ax dx=1ln⁡aax+C
∫sec⁡2x dx=tan⁡x+C
∫sec⁡xtan⁡x dx=sec⁡x+C
∫cosec⁡2x dx=−cot⁡x+C
∫cosec⁡xcot⁡x dx=−cosec⁡x+C
∫1a2+x2 dx=1aarctan⁡(xa)+C
∫1a2−x2 dx=arcsin⁡(xa)+C,|x|<a
  • Exam note: Add +C to every indefinite integral. Keep the modulus in ln⁡|x|.
  • Connection: A boundary condition finds C.

Recognising the form

NameFormulaCondition
Linear inside
∫f(ax+b) dx=1aF(ax+b)+C
F′=f
Top is the derivative of the bottom
∫g′(x)g(x) dx=ln⁡|g(x)|+C
Derivative times exponential
∫g′(x) eg(x) dx=eg(x)+C
  • Connection: sin⁡2x, cos⁡2x: use the double angle formula (Topic 3).
  • Connection: Denominator with two distinct linear factors: partial fractions first (Topic 1).

Substitution and definite integrals

NameFormulaCondition
Substitution
∫f(g(x)) g′(x) dx: let u=g(x), du=g′(x) dx, then find ∫f(u) du
Definite integral
∫abf(x) dx=F(b)−F(a)
F′=f
  • Connection: Example: ∫2x(x2+1)3 dx. Let u=x2+1, so du=2x dx. This gives ∫u3 du=u44+C=(x2+1)44+C.
  • Exam note: Substitution in a definite integral: change the limits to u-values too.

Integration by parts

NameFormulaCondition
By parts
∫udvdx dx=uv−∫vdudx dx or ∫u dv=uv−∫v du
  • Connection: By parts: choose u that gets simpler when differentiated, such as ln⁡x or xn. If ln⁡x is in the integral, take u=ln⁡x. For ∫ln⁡x dx, use dvdx=1.
  • Connection: ∫exsin⁡x dx: parts twice, then the integral appears again. Solve for it.

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Areas, Volumes and Kinematics

Areas

NameFormulaCondition
With the x-axis
A=∫ab|y| dx
A=∫aby dx when y>0
With the y-axis
A=∫ab|x| dy
Between curves
A=∫ab(f(x)−g(x)) dx,f(x)≥g(x)
  • Connection: Below the x-axis, the integral is negative. Split at the roots or integrate |y|.
  • Exam note: Area between curves: find where they meet for the limits.
𝑥𝑦244−4
y=x(x−2)(x−4), 0≤x≤4
area =4+4=8
integral =4+(−4)=0

Volumes of revolution

NameFormulaCondition
About the x-axis
V=∫abπy2 dx
About the y-axis
V=∫abπx2 dy
  • Connection: Square y first: ∫πy2 dx≠π(∫y dx)2
𝑥𝑦𝑦=𝑥
Each slice is a disc of area πy2.

Kinematics

NameFormulaCondition
Velocity, acceleration
v=dsdta=dvdt=d2sdt2
Going back
s=∫v dtv=∫a dt

use the starting values to find C

Displacement from t1 to t2
∫t1t2v(t) dt
Distance travelled from t1 to t2
∫t1t2|v(t)| dt
Speed
|v|
𝑡𝑣4−441349
v=3(t−1)(t−3), 0≤t≤4
displacement =4+(−4)+4=4
distance =4+4+4=12
  • Connection: v>0: moving in the positive direction. v<0: moving in the negative direction.
  • Connection: At rest: v=0. Changes direction: v changes sign.
  • Connection: Speeding up: v and a have the same sign. Slowing down: opposite signs.
  • Connection: Maximum speed from a v–t graph: speed is |v|, so look for the point furthest from the t-axis. It can be above or below the axis.
𝑠0positivedirection⟶𝑣>0:movingright𝑣=0and𝑣changessign:changesdirection𝑣<0:movingleft
Motion along a straight line: s is the displacement from 0.
𝑡𝑣14779𝑣=−9
v=(t−1)(t−7), 0≤t≤7
Furthest from the t-axis: v=−9 at t=4, not v=7 at t=0.
Maximum speed =9.

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Differential Equations

Euler’s method

NameFormulaCondition
Euler’s method
yn+1=yn+h×f(xn,yn)
xn+1=xn+h, h = step length
  • Connection: A smaller h gives a better approximation.
  • Exam note: Keep full accuracy at every step.
𝑥𝑦exactEuler0.511.5
dydx=x+y, y(0)=1, h=0.5

Exact methods

NameFormulaCondition
Variables separable
dydx=f(x) g(y) ⇒ ∫1g(y) dy=∫f(x) dx
Homogeneous
dydx=f(yx): put y=vx, dydx=v+xdvdx
separable in v and x
Integrating factor
y′+P(x) y=Q(x): I=e∫P(x) dx
ddx(Iy)=IQ ⇒ Iy=∫IQ dx
first write the equation in this form
  • Connection: An initial condition finds the constant.
  • Exam note: Add the constant before you divide or take exponentials.

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Maclaurin Series

Standard series

NameFormulaCondition
Maclaurin series
f(x)=f(0)+x f′(0)+x22!f″(0)+⋯
ex
1+x+x22!+⋯
all x
ln⁡(1+x)
x−x22+x33−⋯
−1<x≤1
sin⁡x
x−x33!+x55!−⋯
all x
cos⁡x
1−x22!+x44!−⋯
all x
arctan⁡x
x−x33+x55−⋯
|x|≤1

Building new series

Three separate methods. Each one starts from a standard series.

NameFormulaCondition
Substitution

Replace x in a standard series. Example: e2x comes from the series for ex with x replaced by 2x.

Differentiation or integration

Differentiate or integrate a standard series term by term.

Products

Multiply two standard series and keep the terms up to the power asked.

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Cover of the AA HL Revision Notes PDF, updated November 2026

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