The Unit Circle: Angles, Coordinates and Trig Values
The unit circle explained: why the coordinates are cos and sin, every special angle in degrees and radians, tangent on the unit circle, and memory tricks.
Tag: trigonometry
Read article → The Unit Circle: Angles, Coordinates and Trig Values
Trigonometric Functions: Sin, Cos, Tan, Table and Graphs
The six trig functions with SOH-CAH-TOA and the unit circle, a table of exact values (sin 30, cos 180, sec 45), graphs, period and amplitude.
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.
Special Right Triangles: 45-45-90 and 30-60-90 Rules
The 45-45-90 and 30-60-90 special right triangles: side ratios, where they come from, how to find missing sides, exact trig values and practice problems.
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.
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.
Inverse Trig Functions: Arcsin, Arccos and Arctan
Arcsin, arccos and arctan explained: domains and ranges, how to evaluate them, graphs, derivatives, and the integrals that give inverse trig answers.
Derivative of sin x: Proof, Examples and Trig Derivatives
The derivative of sin x is cos x. See the limit proof, chain rule examples like sin(3x) and sin²x, and the table of all six trig derivatives.
Degrees to Radians and Radians to Degrees: Formula, Chart
Convert degrees to radians (multiply by π/180) and radians to degrees (multiply by 180/π), with a full chart, unit circle radians and examples.
Free Scientific Calculator Online (with DEG/RAD Guide)
A free online scientific calculator with trig in degrees or radians, logs, powers, roots, factorials and scientific notation, plus how to use every key.