Question

prove that cotA-cot 2A-Cosec2A​

Answer 1

Answer:

LHS= cotA - cot 2A

=cos A/sin A - cos 2A /sin 2A

=(cosA sin2A- sinAcos 2A)/(sinAsin2A)

=(Sin 2A cos A - cos2AsinA)/(sinA sin2A)

Here we used sinXcosY-sinYcosX=sin(X-Y)

= sin(2A-A)/(sinAsin2A)

=sinA/(sinAsin2A)

=1/sin2A

=cosec2A

=RHS