# Quotient Identities

**defines the relations for tangent and cotangent in terms of sine and cosine.**

*quotient identity*
and |

**using a familiar 30-60-90 triangle.**

*tangent quotient identity*Substitute the appropriate values into the identity and simplify:

Let's look at the

**using a familiar 45-45-90 triangle.**

*cotangent quotient identity*Substitute the appropriate values into the identity and simplify:

1 = 1

The quotient identities will be used in trigonometric proofs and applications of calculus where using an identity is a more convenient form. Remember that the difference between an equation and an identity is that an identity will be true for ALL values.

Related Links:Math Trigonometry Pythagorean Identities Cofunction Identities |

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