Question

prove that
, sin3theta-sintheta=0​

Answer 1

$\sin( 3 \alpha ) = 3 \sin( \alpha ) - 4 { \sin( \alpha ) }^{3} \\ \\ hence \: \sin(3 \alpha ) - \sin( \alpha ) = \\ 2 \sin( \alpha ) - 4 { \sin( \alpha ) }^{3} \\ (2\sin( \alpha ) )(1 - 2 { \sin( \alpha ) }^{2} ) = \\ 2 \sin( \alpha ) \times \cos(2 \alpha )$

For theta =alpha=0