Question

Sin2x/1+cos2x=tanx
How do I prove this with the double angle law

Answer 1

`sin(2x) = 2 sin x cos x \\ \\ cos(2x) = cos^2 x - sin^2 x`
After Substituting:

`(2 sin x cos x)/(1+cos^2 x - sin^2 x)`
Use pythagorean thm:

`1 - sin^2 x = cos^2 x`
......................

`(2 sin x cos x)/(2cos^2 x) \\ \\ = (sinx )/(cos x) \\ \\ = tan x`