Answer:
Since we know that,
cos2x= cos²x-sin²x=(cosx-sinx)(cosx+sinx)
And, sin2x=2sinx.cosx
Therefore,
1-sin2x= cos²x+sin²x-2sinx.cosx
1-sin2x= (cosx-sinx)²
Then let
y=cos2x/(1-sin2x)
