Question

Prove that SIN(A+B) =SINA. COSB+SINB. COSA​

Answer 1

$\large \bold{ \underline{ \underline{ \:Answer : \: \: \: }}}$

$\to \sin(a + b) = \sin(a) \cos(b) + \cos(a) \sin(b)$

$\large \bold{ \underline{ \underline{ \: Explaination : \: \: \: }}}$

$\to \sin(a + b) \\ \\ \to \cos( \frac{\pi}{2} - (a + b) ) \\ \\ \to\cos(( \frac{\pi}{2} - a) - b) \\ \\ \to \cos( \frac{\pi}{2} - a) \cos(b) + \sin( \frac{\pi}{2} - a ) \sin(b) \\ \\ \to \sin(a) \cos(b) + \cos(a) \sin(b)$