Question

Prove::

cosy=1-x²/1+x²​

Answer 1

Answer:

Step-by-step explanation: I think the question must be cos2y=1-x^2/1+x^2

From given

We know cos2y in terms of tan is 1-tan^2x/1+tan^2x

Let tanx=x

Therefore the answer is cos2y=1-x^2/1+x^2