Question

If A = 45⁰, verify that :
(i) sin 2A = 2 sin A cos A

Answer 1

A= 45⁰ 

^{${\displaystyle \Rightarrow 2A=2\times {45}^0={90}^0}$}

^{(i) sin 2A = sin ${\displaystyle {90}^0=1}$}

2 sin A cos A = 2 sin ${\displaystyle {45}^0{\cos 45}^0=2\times \frac{1}{\sqrt{2}}\times \frac{1}{\sqrt{2}}=1}$

∴ sin 2A = 2 sin A cos A