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  • erplex

    Concept Lessons

    Access comprehensive explorations for all concepts in your objective, including problems, helpful visuals, and AI features.

    What you'll find in every lesson:

    High-quality explanations: Each lesson is carefully crafted to help you truly understand the concept, not just memorize it.

    Checkpoint exercises: Practice as you learn with interactive problems designed to reinforce your understanding.

    AI-powered discussions: Engage with thought-provoking questions that help reveal your misconceptions.

    What you'll find in every lesson:

    High-quality explanations: Each lesson is carefully crafted to help you truly understand the concept, not just memorize it.

    Checkpoint exercises: Practice as you learn with interactive problems designed to reinforce your understanding.

    AI-powered discussions: Engage with thought-provoking questions that help reveal your misconceptions.

    Concept Lessons

    Access comprehensive explorations for all concepts in your objective, including problems, helpful visuals, and AI features.

    102 Lessons Available

    What you'll find in every lesson:

    High-quality explanations: Each lesson is carefully crafted to help you truly understand the concept, not just memorize it.

    Checkpoint exercises: Practice as you learn with interactive problems designed to reinforce your understanding.

    AI-powered discussions: Engage with thought-provoking questions that help reveal your misconceptions.

    What you'll find in every lesson:

    High-quality explanations: Each lesson is carefully crafted to help you truly understand the concept, not just memorize it.

    Checkpoint exercises: Practice as you learn with interactive problems designed to reinforce your understanding.

    AI-powered discussions: Engage with thought-provoking questions that help reveal your misconceptions.

    Cartesian plane & lines

    3 concepts with notes

    Distance, Midpoint, & Gradient

    Distance between two points, midpoint of two points, and finding gradient using two points

    Start Lesson

    Equations of a Line

    Gradient-intercept form, point-gradient form, vertical lines, horizontal lines, standard form of a line

    Start Lesson

    Line Intersections & Systems of Equations

    Parallel and perpendicular lines, intersection of 2 straight lines, solving a two-variable system of equations

    Start Lesson

    Function Theory

    3 concepts with notes

    Functions and their properties

    Domain and range of functions, function as a model, interval notation

    Start Lesson

    Function Graphs

    Graphing functions with a calculator, characteristics of a function, even and odd functions, x and y intercepts, horizontal and vertical asymptotes, maxima and minima

    Start Lesson

    Function Composition & Inverses(Plus Only)

    Composing functions, inverse functions, graphing and evaluating inverse functions, computing inverses and domain restrictions

    Upgrade to Plus

    Modelling

    4 concepts with notes

    Scaling with Logs

    Logarithmic scales, linearizing, and log-log or semi-log graphs

    Start Lesson

    Basic Modelling Skills

    Using functions to fit real world data and make predictions

    Start Lesson

    Advanced Modelling Skills

    More types of modelling, including natural log, sinusoidal, and logistic. More with piecewise models.

    Start Lesson

    Direct and Inverse Proportions

    A lesson on direct and inverse proportions.

    Start Lesson

    Exponents & Logarithms

    4 concepts with notes

    Exponential Algebra

    Exponents, properties of exponents, and solving exponential equations

    Start Lesson

    Logarithm algebra

    Definition and evaluation of logarithms, properties of logs, e and the natural log, change of base rule

    Start Lesson

    Radicals and Roots

    Nth roots, fractional and rational exponents, conjugates.

    Start Lesson

    Exp & Log functions(Plus Only)

    Graphing exponential functions, exponential growth and decay, logarithmic inverse functions.

    Upgrade to Plus

    Approximations & Error

    3 concepts with notes

    Rounding Numbers

    Rounding, significant figures, decimal places

    Start Lesson

    Scientific Notation

    Converting numbers to and from scientific notation (a×10k)

    Start Lesson

    Error

    Approximations error bounds

    Start Lesson

    Sequences & Series

    7 concepts with notes

    Arithmetic Sequences

    Introduction to the definition, properties, and general term of an arithmetic sequence

    Start Lesson

    Geometric Sequences

    Introduction to definition, identification, and general term of geometric sequences

    Start Lesson

    Arithmetic Series(Plus Only)

    Definition of series, formula for arithmetic series

    Upgrade to Plus

    Σ summation notation(Plus Only)

    Summation notation, properties of sums

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    Geometric Series(Plus Only)

    Definition and general term of geometric series, finite and infinite series, convergence

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    Sequence Mode (Calculator)(Plus Only)

    Working with sequences on a calculator, computations and applications of a calculator

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    Compounding (Appreciation & Depreciation)(Plus Only)

    Compound growth, depreciation, interest, inflation, real value

    Upgrade to Plus

    Matrices

    5 concepts with notes

    Foundations of Matrices

    Introduction to the concept of matrices, their properties, and basic matrix operations.

    Start Lesson

    Identity, Inverses & Determinants

    The concept of an identity matrix and inverse matrices, and determinants. Finding inverses with technology, or by hand for (2×2) matrices

    Start Lesson

    Geometric Transformations with Matrices

    Understanding how (2×2) matrices transform points and shapes on the plane. Explanations of the common IB transformations.

    Start Lesson

    Systems of equations with Matrices

    Solving and interpreting systems of linear equations through the lens of matrices.

    Start Lesson

    Eigenvalues & Eigenvectors

    Find eigenvalues & eigenvectors, and using them to diagonalize and find powers of matrices.

    Start Lesson

    Transformations & asymptotes

    4 concepts with notes

    Linear Transformations

    Vertical and horizontal translations, dilations, reflecting over axes

    Start Lesson

    Rational functions(Plus Only)

    Reciprocal functions, quadratic denominators, graphs of rational linear functions

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    Further Transformations(Plus Only)

    Graphing absolute value functions, squared functions, piecewise functions, graphing 1/f(x)

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    Modulus & Inequalties(Plus Only)

    Absolute value, inequalities of functions

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    2D & 3D Geometry

    5 concepts with notes

    Right angled triangles

    Pythagoras's theorem, SOHCAHTOA, finding side length from angles

    Start Lesson

    Non-right-angled triangles(Plus Only)

    Sine and cosine rules, finding general area of a triangle

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    Applied triangle geometry

    Angles of elevation and depression, true bearings, projections and more

    Start Lesson

    Circles: Radians, arcs and sectors(Plus Only)

    Measuring angles in radians, circumference & arc lengths and sector areas

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    3D solids

    Spheres, cylinders, prisms, right cones, right pyramids, and combinations of solids

    Start Lesson

    Voronoi Diagrams

    2 concepts with notes

    Properties of Voronoi Diagrams

    What a Voronoi diagram is, perpendicular bisectors, terminology and construction.

    Start Lesson

    Applications of Voronoi Diagrams

    A deeper dive into common uses of Voronoi diagrams on the IB exam

    Start Lesson

    Trig equations & identities

    4 concepts with notes

    The Unit Circle

    Sine, cosine & tangent functions in the unit circle

    Start Lesson

    Trigonometric Functions

    Graphs, domain, and range of sinx and cosx, general sinusoidal functions, modeling periodic phenomena, tanx and reciprocal trig functions, inverse trig functions

    Start Lesson

    Trig Equations(Plus Only)

    Solving equations involving trigonometric functions and understanding solution domains

    Upgrade to Plus

    Trigonometric Identities(Plus Only)

    Applications of trigonometric identities such as sin2θ+cos2θ=1, sin2θ=2sinθcosθ and more identities for HL students

    Upgrade to Plus

    Complex Numbers

    3 concepts with notes

    Cartesian form

    Arithmetic of complex numbers in cartesian form, including conjugates, and the Argand diagram (complex plane).

    Start Lesson

    Complex Modulus(Plus Only)

    Introduction, definition, and properties of the complex modulus

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    Mod-arg & Polar forms(Plus Only)

    rcisθ and eiθ

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    Vectors

    6 concepts with notes

    Vector arithmetic & geometry

    Addition, subtraction and scalar multiplication, computed algebraically and geometrically

    Start Lesson

    Scalar and vector products

    Introduction and applications of vector and scalar products

    Start Lesson

    Equations of a line(Plus Only)

    Vector form, cartesian form, parametric form, modeling with vectors

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    Coincident, Parallel, Intersecting & Skew Lines(Plus Only)

    Parallel lines in 3D, coincident, skew and intersecting lines

    Upgrade to Plus

    Equations of a plane(Plus Only)

    Vector and scalar product forms of a plane, cartesian equation of a plane

    Upgrade to Plus

    Angles and intersections with planes(Plus Only)

    Intersection of a line and plane, angle between line and plane, intersection and angle between two planes, intersection of 3 planes

    Upgrade to Plus

    Graph Theory

    5 concepts with notes

    Foundations of Graphs

    🚧 🚧 Under construction 🚧 🚧


    Email james@perplex.org to request this lesson urgently.

    Start Lesson

    Adjacency matrices & walks

    🚧 🚧 Under construction 🚧 🚧


    Email james@perplex.org to request this lesson urgently.

    Start Lesson

    Minimum Spanning Trees

    🚧 🚧 Under construction 🚧 🚧


    Email james@perplex.org to request this lesson urgently.

    Start Lesson

    Chinese Postman Problem

    🚧 🚧 Under construction 🚧 🚧


    Email james@perplex.org to request this lesson urgently.

    Start Lesson

    Traveling Salesman Problem

    🚧 🚧 Under construction 🚧 🚧


    Email james@perplex.org to request this lesson urgently.

    Start Lesson

    Differentiation

    7 concepts with notes

    Limits and Derivatives

    The concept (and basic properties) of limits and derivatives

    Start Lesson

    Differentiation rules

    Power rule, chain rule, product rule, quotient rule, derivatives of ex, ax, loga​(x), trigonometric, and inverse trigonometric functions

    Start Lesson

    Tangents and normals(Plus Only)

    Definitions of tangent and normal, finding tangent and normal lines to a function

    Upgrade to Plus

    Applications of the First Derivative(Plus Only)

    Increasing and decreasing intervals, stationary points (maxima and minima), and optimisation

    Upgrade to Plus

    Second Derivatives and Applications(Plus Only)

    Definition of the second derivative, concavity, inflexion points

    Upgrade to Plus

    n^th Derivative(Plus Only)

    Taking the nth derivative, inductive proofs with the nth derivative

    Upgrade to Plus

    Related Rates(Plus Only)

    Types of related rates, implicit differentiation

    Upgrade to Plus

    Integration

    5 concepts with notes

    Definite Integrals, Areas, and Basic Anti-Derivatives(Plus Only)

    Concept of an integral, areas with definite integrals, and basic anti-derivative solving skills

    Upgrade to Plus

    Anti-Derivative Rules

    Antiderivatives of polynomials, trigonometric, inverse trigonometric, exponential, and logarithmic functions

    Start Lesson

    Techniques of Integration(Plus Only)

    The reverse chain rule, integration by substitution, integration by parts, additional strategies

    Upgrade to Plus

    Kinematics(Plus Only)

    Computations involving distance, displacement, velocity, and acceleration

    Upgrade to Plus

    Volumes of Revolution

    Finding the volume of a solid revolved around a function or axis to create a 3D figure

    Start Lesson

    Differential Equations

    4 concepts with notes

    Solving Differential Equations

    An introduction to differential equations and how to solve them.

    Start Lesson

    Euler's Method

    Euler's method as a numerical method for finding particular solutions.

    Start Lesson

    Coupled systems

    Solving coupled systems, and visualizing them with phase portraits.

    Start Lesson

    Second Order Differential Equations

    Solving differential equations with second derivatives using a coupled system technique.

    Start Lesson

    Probability

    5 concepts with notes

    Probabilistic Events

    Theoretical and experimental probability, complementary events, expected number of outcomes, sample space

    Start Lesson

    Combined Events(Plus Only)

    Venn diagrams, intersection and union of events, conditional probability, independent events

    Upgrade to Plus

    Dependence(Plus Only)

    Tree diagrams, selection with/without replacement, dependence

    Upgrade to Plus

    Bayes' Theorem(Plus Only)

    Bayes' theorem with 2 and 3 events, sum of conditional probabilities

    Upgrade to Plus

    Markov Chains

    Under construction

    Start Lesson

    Descriptive Statistics

    7 concepts with notes

    Population & Data

    Understand the basics of population, data collection, and sampling.

    Start Lesson

    Measuring Center

    Learn different ways to measure the "center," or typical values, of a set of data: mean, median, and mode.

    Start Lesson

    Quartiles and Box & Whisker Plots(Plus Only)

    Learn the concept of dispersion, range, IQR, outliers, and box and whisker plots.

    Upgrade to Plus

    Standard Deviation and Variance(Plus Only)

    Learn about standard deviation and variance, which we use to measure how tightly or loosely clustered the data is around the mean.

    Upgrade to Plus

    Frequency Tables, Histograms and cumulative frequency diagrams(Plus Only)

    In this lesson, we learn about different ways to visualize data.

    Upgrade to Plus

    Linear Regression(Plus Only)

    Regressions of y on x, regressions of x on y, the correlation coefficient r, the rank correlation coefficient rs​, extrapolation and interpolation of data.

    Upgrade to Plus

    Data Collection

    A lesson on data collection.

    Start Lesson

    Bivariate Statistics

    2 concepts with notes

    Linear Regression(Plus Only)

    Regressions of y on x, regressions of x on y, the correlation coefficient r, the rank correlation coefficient rs​, extrapolation and interpolation of data.

    Upgrade to Plus

    Non-linear regression & residuals

    🚧 🚧 Under construction 🚧 🚧


    Email james@perplex.org to request this lesson urgently.

    Start Lesson

    Distributions & Random Variables

    5 concepts with notes

    Discrete random variables

    Introduction and properties of random variables, probability distributions, expected value and variance, linear transformations of r.v.'s

    Start Lesson

    Binomial Distribution(Plus Only)

    Concept of the binomial distribution, binomial PDF and CDF, expectation and variance of binomial distribution

    Upgrade to Plus

    Normal Distribution(Plus Only)

    Introduction and definition of the normal distribution, standard deviations, normal and inverse normal calculations, z-values, normal standardization

    Upgrade to Plus

    Poisson Distribution

    The discrete Poisson Distribution

    Start Lesson

    Sampling, combinations and CLT

    A lesson on sampling, combinations and clt.

    Start Lesson

    Inference & Hypotheses

    6 concepts with notes

    Hypothesis Testing and p-values

    Exploring a simplified coin flip example to lay the foundation of null and alternative hypotheses, p-values and significance levels.

    Start Lesson

    χ² tests

    Testing whether observations fit predictions, and whether events are independent, using a χ² distribution.

    Start Lesson

    Further χ² tests & unbiased estimators

    Using chi squared tests where numerical categories need to be combined, and goodness of fit tests using estimated parameters.

    Start Lesson

    Student's t-test

    Using the t-distribution to compare a sample mean to a population mean with unknown variance.

    Start Lesson

    Z-test and Confidence Intervals

    Z-tests when the standard deviation is known, confidence intervals using Z and T distributions, critical values & regions, type Ⅰ vs ⅠⅠ errors.

    Start Lesson

    Binomial & Poisson Tests

    Hypothesis testing using Binomial and Poisson distributions.

    Start Lesson

    Financial Mathematics

    3 concepts with notes

    Compounding (Appreciation & Depreciation)(Plus Only)

    Compound growth, depreciation, interest, inflation, real value

    Upgrade to Plus

    Loans

    A lesson on loans.

    Start Lesson

    Annuities

    A lesson on annuities.

    Start Lesson