Skip to content
Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

College Algebra

The complete college algebra course β€” every idea explained twice, with something to play with along the way.

Free to read now, no account needed: The language of math. Create a free account to open the other chapters, take the quizzes and keep your progress.

2 Fundamentals of algebra πŸ”’

Create a free account to open this chapter.

  • Real numbers and the number line ~15 min
  • Properties of real numbers and order of operations ~20 min
  • Exponents and radicals ~25 min
  • Polynomials and factoring ~30 min
  • Simplifying rational expressions ~20 min
  • Multiplying and dividing rational expressions ~20 min
  • Adding and subtracting rational expressions ~20 min
  • Complex fractions and the difference quotient ~25 min

3 Equations & inequalities πŸ”’

Create a free account to open this chapter.

  • Solving linear equations ~20 min
  • Applications and problem solving ~25 min
  • Absolute value and inequalities ~25 min
  • Quadratic equations ~30 min
  • Rational and radical equations ~30 min
  • Solving rational inequalities ~20 min
  • Polynomial inequalities ~20 min

4 Graphs & functions πŸ”’

Create a free account to open this chapter.

  • Distance and midpoint ~20 min
  • Symmetry and circles ~25 min
  • Slope and line equations ~25 min
  • Parallel and perpendicular lines ~25 min
  • Function fundamentals ~25 min
  • Reading function graphs ~10 min
  • Average rate of change ~10 min
  • Even and odd functions ~8 min
  • Piecewise and step functions ~12 min
  • Transformations of functions ~25 min
  • Composition and inverse functions ~25 min

5 Polynomial & rational functions πŸ”’

Create a free account to open this chapter.

  • Quadratic models ~35 min
  • Graphs of polynomial functions ~25 min
  • Dividing polynomials with long division ~8 min
  • Synthetic division, the speed-run ~7 min
  • The Remainder and Factor Theorems ~7 min
  • The Rational Zero Theorem ~8 min
  • Complex numbers and the Fundamental Theorem ~25 min
  • Locating zeros with the Intermediate Value Theorem ~6 min
  • Descartes' Rule of Signs ~7 min
  • The Upper and Lower Bound Theorem ~6 min
  • Irrational zeros travel in pairs ~6 min
  • Asymptotes, holes, and graphs of rational functions ~25 min

6 Other functions, variation & modeling πŸ”’

Create a free account to open this chapter.

  • Square and cube root functions ~20 min
  • Power functions and end behavior ~20 min
  • Absolute value functions ~20 min
  • Direct and inverse variation ~20 min
  • Joint and combined variation ~20 min
  • Regression and correlation ~25 min
  • Choosing a model type ~20 min
  • Fitting a model to data ~25 min

7 Exponential & logarithmic functions πŸ”’

Create a free account to open this chapter.

  • Exponential functions ~25 min
  • Logarithms ~25 min
  • Solving exponential and logarithmic equations ~18 min
  • Half-life and doubling time ~10 min
  • Newton's Law of Cooling ~10 min
  • Expanding and condensing logarithms ~25 min
  • Logarithmic scales ~20 min
  • Logistic growth models ~20 min
  • Exponential and logarithmic inequalities ~18 min

8 Trigonometric functions πŸ”’

Create a free account to open this chapter.

  • Angles and standard position ~20 min
  • Radian measure ~25 min
  • Arc length and sector area ~20 min
  • Linear and angular speed ~20 min
  • The six trigonometric ratios ~25 min
  • Special right triangles ~20 min
  • Solving right triangles ~25 min
  • The unit circle definitions ~25 min
  • Reference angles and exact values ~25 min
  • Domain, range, and period ~25 min

9 Graphs of trigonometric functions πŸ”’

Create a free account to open this chapter.

  • Graphing sine and cosine ~20 min
  • Amplitude, period, and phase shift ~25 min
  • Graphing tangent, cotangent, secant, and cosecant ~20 min
  • Modeling with sinusoids ~25 min
  • Simple harmonic motion ~20 min

10 Trigonometric identities & equations πŸ”’

Create a free account to open this chapter.

  • Reciprocal, quotient, and Pythagorean identities ~25 min
  • Even, odd, and cofunction identities ~20 min
  • Simplifying and verifying trigonometric identities ~25 min
  • Sum and difference formulas ~25 min
  • Combining sine and cosine into a single sinusoid ~20 min
  • Exact values and reduction formulas ~20 min
  • Double-angle identities ~25 min
  • Power-reduction and half-angle identities ~25 min
  • Product-to-sum and sum-to-product identities ~20 min
  • Why domains must be restricted ~20 min
  • Inverse sine, cosine, and tangent ~20 min
  • Compositions of trig and inverse trig functions ~25 min
  • Basic equations on an interval ~25 min
  • Equations requiring identities ~25 min
  • Multiple-angle equations ~25 min

11 Applications of trigonometry πŸ”’

Create a free account to open this chapter.

  • Oblique triangles and the Law of Sines ~20 min
  • The ambiguous case: SSA ~20 min
  • Law of Cosines: SAS and SSS triangles ~25 min
  • Triangle area and Heron's formula ~20 min
  • Angles of elevation, depression, and bearings ~25 min
  • Surveying and real-world trig models ~25 min
  • Geometric and component vectors ~25 min
  • Vector arithmetic and unit vectors ~25 min
  • Dot product and projection ~25 min
  • Modulus, argument, and polar form ~20 min
  • Products, quotients, and De Moivre's Theorem ~25 min
  • nth roots of complex numbers ~25 min

12 Analytic geometry πŸ”’

Create a free account to open this chapter.

  • Circles and ellipses ~25 min
  • Parabolas and hyperbolas ~30 min
  • Identifying a conic from its equation ~20 min
  • Rotation of axes ~25 min
  • Translated conics and completing the square ~25 min
  • The polar coordinate system ~20 min
  • Converting between polar and rectangular ~25 min
  • Graphing polar curves ~25 min
  • Polar equations of the conics ~20 min
  • Parametric curves and plotting ~20 min
  • Eliminating the parameter ~20 min
  • Projectile motion with parametric equations ~20 min

13 Systems, matrices & inequalities πŸ”’

Create a free account to open this chapter.

  • Systems of linear equations ~25 min
  • Matrices and row reduction ~35 min
  • Computing determinants ~13 min
  • Cramer's Rule and the 2Γ—2 Matrix Inverse ~8 min
  • Finding a Matrix Inverse ~12 min
  • Matrix Transpose ~3 min
  • Distinct linear factors ~25 min
  • Repeated linear factors ~25 min
  • Irreducible quadratic factors ~25 min
  • Nonlinear systems: substitution and elimination ~25 min
  • Graphing systems of inequalities ~20 min
  • Linear programming ~25 min

14 Sequences, series & probability πŸ”’

Create a free account to open this chapter.

  • Arithmetic and geometric sequences ~28 min
  • Series and the Binomial Theorem ~30 min
  • Counting, permutations, combinations, and probability ~22 min
  • Permutations with repeated objects ~10 min
  • Expected value ~10 min
  • Conditional probability ~20 min
  • The induction principle ~25 min
  • Proving summation formulas ~25 min
  • Divisibility and inequalities by induction ~25 min
  • Odds, Bayes' theorem, and binomial probability ~24 min
  • Annuities and amortization ~20 min