Question

Prove this equation ​

Answer 1

your question...

(sintheta - 2sin³theta)/(2cos³theta-costheta)

sintheta (1-2sin²theta)/cos2theta(2cos²theta-1)

Such that...

1-2sin²theta= cos2theta

2cos²theta-1=cos2theta

sintheta.cos2theta/cos2theta.cos2 theta

=sintheta/cos2theta

=tan theta

proved your question