Trigonometric Identities

The Trigonometric Identities are equations true for Right Angled Triangles.

Each side of a right triangle has a name:

• Perpendicular

• Hypotenuse

• Base

These terms are represented in figure below:

• There are 3 main functions in trigonometry named Sine, Cosine and Tangent.

• They are ratio of the length of one side to the other.

• For a right triangle with an angle θ :

Sine Function:

sin(θ) = Perpendicular / Hypotenuse

Cosine Function:

cos θ = Base / Hypotenuse

Tangent Function:

tan θ = Perpendicular / Base