Question

How can we express sin in terms of tan?

Answer 1

tan= sin/cos
therefore..sin=tan•cos

Answer 2

$\tan( \alpha ) = \frac{ \sin( \alpha ) }{ \cos( \alpha ) } \\ or \: \tan( \alpha ) = \frac{ \sin( \alpha ) }{ \sqrt{1 - {sin}^{2} \alpha } }$
hope this helps