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.
Hello xwrath..,
$\displaystyle \sin \theta=\frac{DC}{2}$
$\displaystyle \boxed{DC=2\sin \theta}$
$\displaystyle \cos \theta=\frac{AD}{2}$
$\displaystyle \boxed{AD=2\cos \theta}$
$\displaystyle \sin \theta=\frac{DX}{2\cos \theta}$
$\displaystyle \boxed{DX=2\sin \theta \cos \theta}$
$\displaystyle \boxed{\sin 2\theta=2\sin \theta \cos \theta}$
$\displaystyle \boxed{DX=\sin 2\theta}$