IB Math AI SL Revision Notes
Formulas, conditions, key connections and common exam traps across the five AI SL topics. Use it alongside the formula booklet and regular question practice.
For the current AI SL syllabus, for exams up to November 2028.
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
Numbers and Approximation
Standard form and accuracy
| Name | Formula | Condition |
|---|---|---|
| Standard form | , |
- Connection: Standard form products: multiply the parts, add the powers of 10, then rescale to .
- Exam note: The GDC shows 4.52Eโ4. Write .
- Exam note: Give answers exactly or to 3 significant figures, unless the question says otherwise.
- Exam note: Keep full calculator values in your working. Round only the final answer.
Percentage error
| Name | Formula | Condition |
|---|---|---|
| Percentage error | = exact value = approximate value |
- Exam note: Percentage error divides by the exact value .
Sequences and Series
Arithmetic and geometric sequences
| Item | Arithmetic common difference | Geometric common ratio |
|---|---|---|
| th term | ||
| Sum of terms | ||
| Finding or |
- Exam note: counts terms, so .
Sums and sigma notation
| Name | Formula | Condition |
|---|---|---|
| Sigma notation | runs through whole numbers |
- Connection: For any sequence:
for - Exam note: In sigma notation, check the first and last values of .
Financial Mathematics
Compound interest and depreciation
| Name | Formula | Condition |
|---|---|---|
| Compound interest | = future value, = present value, = number of years, = number of compounding periods per year, = nominal annual rate of interest | geometric, ratio per period |
| Depreciation | = starting value, = value after years, = annual rate of depreciation | geometric, ratio per year |
- Exam note: Number of years to reach a target: the answer is not a whole number. Round up to the next whole compounding period (to whole years when compounding is yearly).
Loans and annuities
| TVM solver entry | Meaning |
|---|---|
number of payments | |
annual interest rate | |
present value: the amount borrowed or invested at the start | |
payment each period | |
future value: the amount at the end | |
payments per year | |
compounding periods per year |
- Connection: Loan fully repaid:
- Connection: Total repaid: add up all the payments. That is the number of payments times the amount of each payment.
- Connection: Interest paid: the total repaid minus the amount borrowed.
- Exam note: Money paid out is negative and money received is positive.
- Exam note: Write down the values you enter in the TVM solver. They earn method marks.
- Exam note: Monthly payments: . Set from the question.
Exponents and Logarithms
Exponent laws
| Name | Formula | Condition |
|---|---|---|
| Same base | ||
| Zero and negative |
Logarithms
| Name | Formula | Condition |
|---|---|---|
| Definition of a log | , , | |
| Base 10 and base |
- Connection: and
- Connection: and
- Exam note: On the GDC, log is base 10 and ln is base .
- Exam note: To find an unknown power, use the GDC solver.
Systems of Linear Equations
Systems of linear equations
- Exam note: Systems of up to 3 equations and polynomial equations: solve on the GDC, but write the equations first.
Topic 2 Functions
Straight Lines
Equations and gradients
| Name | Formula | Condition |
|---|---|---|
| Straight line | ||
| Gradient | ||
| Parallel lines | ||
| Perpendicular lines |
- Connection: In a linear model, is the change in for each unit increase in and is the value at .
- Exam note: usually needs whole numbers , and .
- Exam note: A vertical line is . Its gradient is undefined.
Functions and Inverses
Functions
| Name | Formula | Condition |
|---|---|---|
| Function | Each in the domain gives exactly one | |
| Domain, range | Domain: the allowed inputs. Range: the outputs. |
- Exam note: In a model, the domain comes from the context, for example .
Inverse functions
- Connection: The graph of is the reflection of in .
- Connection: Domain of = range of
Range of = domain of - Exam note: is not .
Polynomial and Variation Models
Quadratic models
| Form | Equation | What it shows |
|---|---|---|
| Standard | -intercept axis of symmetry vertex | |
| Factor | zeros and axis of symmetry | |
| Vertex | vertex axis of symmetry |
- Connection: : minimum at the vertex. : maximum at the vertex.
- Exam note: Check the maximum or minimum lies inside the domain of the model.
Cubic models
| Name | Formula | Condition |
|---|---|---|
| Cubic | At most 2 turning points |
- Exam note: Zeros, turning points and intersections: use the GDC.
Direct and inverse variation
| Name | Formula | Condition |
|---|---|---|
| Direct variation | is directly proportional to : The graph passes through the origin. With it is a straight line. | |
| Inverse variation | is inversely proportional to : Asymptotes and . |
- Exam note: โ is proportional to โ means . โ is inversely proportional to โ means . Find from one data point.
Exponential Models
Exponential models
| Name | Formula | Condition |
|---|---|---|
| Exponential | asymptote |
- Connection: The value at is .
- Connection: : growth and decay
- Exam note: In , the initial value is , not .
- Exam note: Long-term value: let . Exponential decay tends to .
Sinusoidal Models
Sinusoidal models
| Name | Formula | Condition |
|---|---|---|
| Sinusoidal |
| Feature | From the function | From the graph |
|---|---|---|
| Amplitude | ||
| Period | from a maximum to the next maximum, or from a minimum to the next minimum then | |
| Principal axis | ||
| Maximum, minimum | the highest and lowest -values |
- Exam note: Set the GDC to degrees.
Modelling
Choosing and using a model
- Exam note: Choose a model from the shape of the data and the context. Give a reasonable domain.
- Exam note: Predictions far outside the data are not reliable.
- Exam note: โSketchโ: show the shape and key features. โDrawโ: plot accurately to scale.
- Exam note: Label intercepts, turning points, asymptotes and end points of the domain.
Topic 3 Geometry and Trigonometry
3D Geometry and Triangles
Points in 3D
| Name | Formula | Condition |
|---|---|---|
| Distance | ||
| Midpoint |
Solids
| Name | Formula | Condition |
|---|---|---|
| Right pyramid | = area of base, = height | |
| Right cone | curved surface total surface , = slant height | |
| Sphere | ||
| Hemisphere | curved surface |
Right-angled triangles
| Name | Formula | Condition |
|---|---|---|
| Ratios | ||
| Pythagoras | = hypotenuse |
Angle between a line and a plane
- Connection: Drop a perpendicular from a point on the line to the plane. This gives the projection of the line on the plane.
- Connection: is the angle between the line and its projection. Find it in that right-angled triangle.
Any triangle
| Name | Formula | Condition |
|---|---|---|
| Sine rule | ||
| Cosine rule | ||
| Area |
| Use the sine rule when you know | Use the cosine rule when you know |
|---|---|
|
|
|
|
- Exam note: Draw and label a diagram from the words first.
Elevation, depression and bearings
| Name | Formula | Condition |
|---|---|---|
| Elevation, depression | Measured from the horizontal | |
| Bearings | Measured clockwise from north, with three figures, for example |
Circles
Arcs and sectors
| Name | Formula | Condition |
|---|---|---|
| Arc length | degrees | |
| Sector area | degrees |
Voronoi Diagrams
Perpendicular bisectors
| Name | Formula | Condition |
|---|---|---|
| Perpendicular bisector of | Through the midpoint of , gradient Every point on it is equidistant from and . |
- Connection: Equation:
- Connection: horizontal: the bisector is . vertical: the bisector is .
Voronoi diagrams
| Name | Formula | Condition |
|---|---|---|
| Cell | All points closer to its site than to any other site | |
| Edge | Part of the perpendicular bisector of two sites | |
| Vertex | Where at least three edges meet. | |
| Nearest neighbour interpolation | A point takes the value of the site whose cell contains it |
- Connection: Adding a site: draw the bisectors between the new site and its neighbours, then remove the old edges inside the new cell.
- Connection: The bisectors of and meet at a point equidistant from , and , so the bisector of passes through it too.
Topic 4 Statistics and Probability
Sampling and Data
Data and sampling methods
| Name | Formula | Condition |
|---|---|---|
| Types of data | Discrete data is counted. Continuous data is measured. | |
| Simple random | Every possible sample of that size is equally likely | |
| Systematic | Every th member from a list | |
| Stratified | Each group in proportion: | |
| Quota | A fixed number from each group, not chosen at random | |
| Convenience | The members easiest to reach |
- Connection: Random sampling reduces bias. Quota and convenience samples are not random.
Descriptive Statistics
Mean and spread
| Name | Formula | Condition |
|---|---|---|
| Mean | ||
| Grouped data | Mid-interval values as . Modal class: highest frequency. | gives an estimate |
| Standard deviation | from the GDC. Variance |
- Connection: Add to every value: . and IQR unchanged.
- Connection: Multiply every value by : , ,
- Exam note: Use from the GDC for the standard deviation of the data.
Quartiles, box plots and histograms
| Name | Formula | Condition |
|---|---|---|
| Interquartile range | ||
| Outlier | below or above | |
| Cumulative frequency | read across at for , for the median, for |
- Exam note: Remove an outlier only if it is an error.
- Exam note: Histograms of continuous data have no gaps between bars.
Correlation and Regression
Correlation
| Name | Formula | Condition |
|---|---|---|
| Pearsonโs | linear correlation | |
| Spearmanโs | First rank the data for each variable. Then find Pearsonโs of the ranks. | tied ranks: use the average |
- Connection: close to : strong linear correlation. close to 0: weak or no linear correlation.
- Connection: : always increasing, not always linear. is less affected by outliers than .
- Connection: Scatter diagram: plot each pair as a point. A line of best fit drawn by eye passes through the mean point .
- Exam note: Use for linear data and for non-linear but monotonic data.
- Exam note: Correlation does not mean causation.
Regression line
| Name | Formula | Condition |
|---|---|---|
| Regression line of on | : predicts from |
- Connection: For each increase of 1 in , changes by .
When , . - Connection: The line passes through .
- Exam note: Interpolation is reliable when the correlation is strong ( is close to ). Extrapolation is not reliable.
Probability
Basic rules
| Name | Formula | Condition |
|---|---|---|
| Probability of | , equally likely outcomes | |
| Complementary events | ||
| Combined events | ||
| Mutually exclusive | ||
| Expected number | for trials with probability |
- Connection:
Conditional probability and independence
| Name | Formula | Condition |
|---|---|---|
| Conditional | ||
| Independent |
- Connection: Independent
- Connection: Mutually exclusive events with non-zero probabilities are never independent.
- Exam note: โGiven thatโ means conditional: divide by the probability of the given event.
Tree diagrams
- Connection: Multiply along branches and add the end results.
- Connection: A conditional probability from a tree: the branch you want over all branches that give the condition.
- Exam note: Without replacement, the second-stage probabilities change.
Binomial Distribution
Discrete random variables
| Name | Formula | Condition |
|---|---|---|
| Discrete distribution |
- Connection: Fair game:
Binomial distribution
| Name | Formula | Condition |
|---|---|---|
| Binomial |
- Connection: Conditions: fixed , two outcomes, constant , independent trials
- Connection:
- Exam note: GDC: pdf for and cdf for .
- Exam note: โAt leastโ, โmore thanโ and โfewer thanโ: rewrite with before using the cdf.
Normal Distribution
The normal distribution
| Name | Formula | Condition |
|---|---|---|
| Normal | , variance |
- Exam note: gives the variance. Take the square root for .
- Exam note: Inverse normal: check which tail the GDC uses.
Hypothesis Tests
Setting up a test
| Name | Formula | Condition |
|---|---|---|
| Hypotheses | : no effect or no change. : what you are testing for. | |
| One-tailed, two-tailed | One-tailed: uses or . Two-tailed: uses . | |
| Decision | -value significance level: reject |
- Exam note: Conclude in context: โThere is sufficient evidence at the 5% level thatโฆโ
- Exam note: Never say is proved. Say โdo not reject โ.
Choosing the test
| You are testing | Test | Use when | ||
|---|---|---|---|---|
| two means | two-sample -test | independent samples from normal populations. Pooled: equal variances. | ||
| independence | test for independence | independent | not independent | a contingency table |
| a distribution | goodness of fit | the data fit | the data do not fit | frequencies in classes |
Tests
tests
| Test | Expected frequency | Degrees of freedom | |
|---|---|---|---|
| Independence | the two variables are independent | rows, columns | |
| Goodness of fit | the data fit the given distribution | total frequency probability of the class | number of classes |
- Connection: observed frequency: the counts in the data. expected frequency: the counts you would expect if were true.
- Connection: The GDC gives and the -value. Reject when the -value significance level.
- Exam note: Every expected frequency must be at least 5. If not, combine classes and reduce .
Topic 5 Calculus
Derivatives, Tangents and Normals
The derivative
| Name | Formula | Condition |
|---|---|---|
| Derivative | : the gradient function and the rate of change of with respect to | |
| Power rule |
- Connection: The derivative is the limit of the gradient of a chord as the chord shrinks.
- Connection: Rewrite first:
Tangents and normals
| Name | Formula | Condition |
|---|---|---|
| Tangent at | ||
| Normal at |
- Connection: The normal is perpendicular to the tangent.
- Exam note: Find from , not from .
- Exam note: GDC: the derivative at a point and the tangent line can be checked.
tangent , normal
Stationary Points and Optimisation
Shape of a graph
| If | Then |
|---|---|
is increasing | |
is decreasing | |
stationary point at |
- Connection: turns where and changes sign.
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.
- Exam note: Give the value of the quantity as well as the where it occurs, if asked.
Integration
Standard integrals
- Connection: A boundary condition finds .
- Connection: Integration reverses differentiation: check by differentiating.
- Exam note: Add to every indefinite integral.
Definite integrals
| Name | Formula | Condition |
|---|---|---|
| Definite integral | the GDC gives the value |
Areas and the Trapezoidal Rule
Areas
| Name | Formula | Condition |
|---|---|---|
| With the -axis | when |
Trapezoidal rule
| Name | Formula | Condition |
|---|---|---|
| Trapezoidal rule |
- Connection: More strips give a better estimate.
- Exam note: strips need values of .
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19 pages ยท 5 topics ยท 26 sections
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Last updated: November 2026.
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