Question

1+ cos2x =
2/1+tan ²x

Answer 1

Use the Pythagorean identity to rewrite the tangent:

$\dfrac2{1+\tan^2x}=\dfrac2{\sec^2x}=2\cos^2x$

Then use the double angle identity for cosine:

$\cos^2x=\dfrac{1+\cos(2x)}2$

$\implies2\cos^2x=1+\cos(2x)$

and the identity is proved.

Answer 2

sure but 1st show every1 wut u know