Solve the differential equation `(dy)/(dx)=(1-cos2y)/(1+cos2y)`.

Explanation

`(dy)/(dx)=(1-cos2y)/(1+cos2y)`
`=(2sin^(2)y)/(2cos^(2)y)=tan^(2)y`
`implies cot^(2)ydy=dx`
`implies intcot^(2)ydy=intdx+c`
`implies int(cosec^(2)y-1)dy=intdx+c`
`implies-coty-y=x+c`.