Respuesta :

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)