Question

=1-2sin^2(Π/16)cos^2(Π/16)+1-2sin^2(3Π/16)cos^2(3Π/16)
=2-(sinΠ/4)^2/2-(sin3Π/4)^2/2

Can anyone explain how we got the second expression from the first one ?

Answer 1

@Peter14

Answer 2

try factoring stuff and see what happens?

Answer 3

I used 2sinAcosA = sin2A
I got 2 - 1/2*sinΠ/8 - 1/2*sin3Π/8
What do I do next ?

Answer 4

What do you need to do with this eq'n? Are you going to prove it or what?