Prove

Question

cotx-1/cotx+1=1-sin2x/cos2x

Answer 1

changing all to sinx and cosx, we have on the left:

(cos/sin - 1)/(cos/sin + 1)
= (cos-sin)/sin / (cos+sin)/sin
= (cos-sin)/(cos+sin)
= (cos-sin)^2 / (cos^2-sin^2)
= (cos^2 - 2sin*cos + sin^2)/(cos^2-sin^2)
= (1-sin2x)/cos2x

Answer 2

you are stupid