Now separating variable x on one side and variable y on another side, we have,
– cot(x) dx = sec2y cot(y) dy
Integrating both sides we get,
Using identities:
– log| sinx | = log| tany | + c
Using: log(a) + log(b) = log(ab)
log( sin x tan y) = log c
sin(x) tan(y) = c