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