Trig Identities: Full List with Double Angle Formulas
Every trig identity you need: Pythagorean, reciprocal, sum and difference, double angle and half angle formulas, with proofs and worked examples.
Tag: precalculus
Read article → Trig Identities: Full List with Double Angle Formulas
Slope Formula: Point-Slope and Slope-Intercept Form
How to find the slope of a line from two points, a graph or an equation, plus point-slope and slope-intercept form, parallel and perpendicular lines.
Precalculus: What It Covers and What You Need for Calculus
What precalculus covers (functions, polynomials, exponentials, logs, trig, sequences), how hard it is, and a study plan with free guides and calculators.
Polynomials: Definition, Degree, Zeros and Graphs Explained
What a polynomial is, degree and leading coefficient, finding zeros by factoring, the rational root test and synthetic division, and end behavior.
Logarithm Rules: Log Properties, Change of Base, Graphs
All the log rules (product, quotient, power, change of base) with proofs, plus how to solve log and exponential equations and graph a log function.
Law of Sines and Law of Cosines: When to Use Each
The law of sines and law of cosines: formulas, how to choose (SSS, SAS, ASA, AAS, SSA), the ambiguous case, proofs, triangle area and examples.
Graphs of Functions: Parent Graphs, Transformations, Range
How to graph any function: parent graphs, shifts, stretches and reflections, intercepts, symmetry, asymptotes, and reading the range from a graph.
Exponential Functions: Definition, Graphs, Growth and Decay
Exponential functions explained: graphs and asymptotes, the number e, growth and decay models, compound interest, and solving exponential equations.
Domain and Range of a Function: How to Find Them
How to find the domain and range of a function from its equation or graph, with interval notation, asymptotes, inverse functions and worked examples.
Distance Formula and Midpoint Formula with Examples
The distance and midpoint formulas: where they come from, examples with negative coordinates, finding a missing endpoint, 3D distance and practice.