Question

find
$\sin(0) = \cos(0)$

Answer 1

$\sin( \beta ) = \cos( \beta ) \\ \\ \frac{ \sin( \beta ) }{ \cos( \beta ) } = 1 \\ \\ \tan( \beta ) = 1 \\ \\ \beta = { {\tan}^{ - 1} (1) } = n\pi + \frac{\pi}{4}$