Posted by **Abby** on Sunday, February 28, 2010 at 11:40am.

1) Use the cofunction identites to evaluate the expression without the aid of a calculator.

cos^2 18 degrees + cos^2 72 degrees.

Would I use the forumula

cos(pi/2 - Q) = sin Q

- Math(Please check) -
**Reiny**, Sunday, February 28, 2010 at 12:06pm
see previous post

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