Convert cotx in form of sinx and cosx.

⇒

∴ The equation now becomes

⇒

⇒

⇒

Assume cosx + sinx = t

∴ d(cosx + sinx) = dt

= cosx - sinx

∴ dt = cosx – sinx

⇒

= ln|t| + c

But t = cosx + sinx

∴ ln|cosx + sinx| + c.