an interesting integral

[@ahmedsabri-ng2xx]

an interesting integral

[@peacefultime3244]

Substitution method?

[@seegeeaye]

Yes

[@Qartikyadav]

Can't we just put ln(cosx)=u and do it...?

[@seegeeaye]

@@Qartikyadav yes, if follow ups are right and solve the problem

[@DimitriNakamoto]

U forgot simplest method to solve this i.e. by parts

[@Samir-zb3xk]

Easiest way is to rewrite ln(cos(x)) as -ln(sec(x))
Then we can use ∫f(x)f'(x)dx = (f(x))²/2 + C