Prove

cot(theta)-tan(theta)=2cot(theta)

LS:

So far I have

cos(theta)/sin(theta)-sin(theta)/cos(theta)

=[cos^2(theta)-sin^2(theta)]/sin(theta)cos(theta)

=cos2(theta)/sin(theta)cos(theta)

I am stuck as to where to go now.

Can someone help me please?