Question

Prove that:Cos18-sin18=^2sin 27

Answer 1

I think it is √2sin 27



To prove that, cos 18 - sin 18 = root 2 sin 27, we can prove that (cos 18 - sin 18)/ root2 = sin27.
=1/root 2*cos 18 - 1/root2 * sin 18
=sin 45*cos18 - cos 45*sin18
=sin(45-18)
= sin27





Hope it helps you