Trigonometric Identities

For a right triangle with angle

For a right triangle with angle A: sin A = opposite/hypotenuse, cos A = adjacent/hypotenuse, tan A = opposite/adjacent, and their reciprocals cosec A

This is the most important trigonometric

This is the most important trigonometric identity. It states that for any angle θ, the sum of squares of sine and cosine always equals 1. Proof: In a

This identity relates tangent and secant

This identity relates tangent and secant functions. It can be proved geometrically using a right triangle or algebraically by dividing the first ident

This identity connects cotangent and cosecant

This identity connects cotangent and cosecant functions. It can be proved by dividing the first identity (sin²θ + cos²θ = 1) by sin²θ throughout. This

Using the three fundamental identities

Using the three fundamental identities, any trigonometric ratio can be expressed in terms of any other ratio. For example: sin θ can be written as √(1