How does sin2x divided by 1-cosx equal 1 plus cosx?

sin2x / (1-cos x) = (1-cos2x) / (1-cos x) = (1-cos x)(1+cos x) / (1-cos x) = (1+cos x)

sin2x=1-cos2x as sin2x+cos2x=1

1-cos2x = (1-cos x)(1+cos x) as a2-b2=(a-b)(a+b)