Homework Statement
Hi,
I must show that (\int cos(x)f(x)dx)^2 <= 2 \int cos(x)f(x)^2dx
(the integrals are from -pi/2 to pi/2)
The Attempt at a Solution
I know that I should use cauchey-schwarz inequality to solve this where <f,g> = \int f(x)g(x)dx In this case i just set g(x) = cos x...