Sections:

Trigonometric Identities and Equations, Page 3

Reciprocal Identities

The first set of identities that needs to be discussed is reciprocal identities. These should look very familiar from your work in previous units.

For all values of theta, (where defined), the following are true:

sine of theta = one over cosecant of theta; cosecant of theta = one over sine of theta; cosine of theta = one over secant of theta; secant of theta = one over cosine of theta; tangent of theta = one over cotangent of theta; cotangent of theta = one over tangent of theta