Friday, October 29, 2010

Identities

Identity- An equation that is always true
Ex: 2x+5 = 2(x-3) + 11 <---- No matter what you put in for X the sides will always be equal

Identities are used for substitution

Reciprocal Identities:
















Quotient Identities:






Pythagorean Identities:

Pythagorean Identities can be derived from other equations. Such as-









Using those two factors we can derive the first pythagorean identity by using the pythagoean theorem and finding a new identity that we can use to substitute.

Plug in the factors

distribute the square

factor out a c^2

divide by c^2 to get the first Pythagorean identity

The other two identities can be derived in a similar way. The three Pythagorean identities are:

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