# Powers of Trigonometric Functions

• March 17th 2010, 06:35 PM
purplec16
Powers of Trigonometric Functions
$8 cos^2 x$

Rewrite the expression as an equivalent expression that does not contain powers of triogonometric functions greater than 1.
• March 17th 2010, 06:52 PM
skeeter
Quote:

Originally Posted by purplec16
$8 cos^2 x$

Rewrite the expression as an equivalent expression that does not contain powers of triogonometric functions greater than 1.

power reduction identity ...

$\cos^2{x} = \frac{1+\cos(2x)}{2}$

... it comes from the double angle identity for cosine.