# Trigonometric Substitution

In mathematics, trigonometric substitution is the substitution of trigonometric functions for other expressions. One may use the trigonometric identities to simplify certain integrals containing radical expressions:

• If the integrand contains a2 − x2, let
and use the identity

• If the integrand contains a2 + x2, let
and use the identity

• If the integrand contains x2 − a2, let
and use the identity

Read more about Trigonometric SubstitutionSubstitutions That Eliminate Trigonometric Functions

### Other articles related to "trigonometric substitution, substitution, trigonometric":

Trigonometric Substitution - Substitutions That Eliminate Trigonometric Functions
... Substitution can be used to remove trigonometric functions ... In particular, see Weierstrass substitution ...

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Virtue is the adherence in action to the nature of things, and the nature of things makes it prevalent. It consists in a perpetual substitution of being for seeming, and with sublime propriety God is described as saying, I A—.
Ralph Waldo Emerson (1803–1882)