Prove? cotx-tanx = cos2x/sinxcosx

1 Answer
Mar 21, 2018

See explanation

Explanation:

We want to verify the identity

cot(x)tan(x)=cos(2x)sin(x)cos(x)

Remember the identity

  • cos(2x)=cos2(x)sin2(x)

RHS=cos(2x)sin(x)cos(x)

RHS=cos2(x)sin2(x)sin(x)cos(x)

RHS=cos2(x)sin(x)cos(x)sin2(x)sin(x)cos(x)

RHS=cos(x)sin(x)sin(x)cos(x)

RHS=cot(x)tan(x)=LHS