The directions:
Evaluate the following using the double angle identities:
The Problem:
4cos^2(pi/8) - 2
My question: Where do I even begin?
Thanks for any help.
Evaluate the following using the double angle identities:
The Problem:
4cos^2(pi/8) - 2
My question: Where do I even begin?
Thanks for any help.
-
4cos^2(Π/8) - 2
= 2 [2cos^2(Π/8) - 1 ]
= 2 cos( Π/4) [ recall that 2cos^2(A) - 1 = cos(2A) ]
= 2 /√2
= √2
= 2 [2cos^2(Π/8) - 1 ]
= 2 cos( Π/4) [ recall that 2cos^2(A) - 1 = cos(2A) ]
= 2 /√2
= √2