Trigonometric Identities

Explanation

Trigonometric identities are equations true for all angles.

Key identities:

1. Pythagorean identities:

   • sin²x + cos²x = 1

   • 1 + tan²x = sec²x

   • 1 + cot²x = csc²x

2. Reciprocal identities:

   • csc x = 1 / sin x

   • sec x = 1 / cos x

   • cot x = 1 / tan x

3. Quotient identities:

   • tan x = sin x / cos x

   • cot x = cos x / sin x

Example:
If sin θ = 3/5, cos θ = 4/5 → sin²θ + cos²θ = 9/25 + 16/25 = 25/25 = 1 ✅