http://www.mathhelpforum.com/math-he...9-untitled.bmp

Diagonals = 2 units

(a) Find AD and DC in terms of θ.

(b) Show that DX = sin2θ.

(c) Hence deduce that sin2θ = 2sinθcosθ

Could someone please show me how to start this question? I've been pondering on it for ages.