Trigonometry is a branch of mathematics that studies relationships involving lengths and angles of triangles (Wikipedia).
There are six main trigonometric functions:
- Sine (sin)
- Cosine (cos)
- Tangent (tan)
- Secant (sec)
- Cosecant (csc)
- Cotangent (cot)
Trigonometric formula (onlinemathlearning.com)
Trigonometric values of common angles (talentsprint.com)
