when do we have to assume and make a substitution in integration.....and how to make correct substitution?

There are many kind of integrand where if we go by substitution, then the problem become so easy. The main thing to look for the substitution is that if you have function and its derivative in the integrand (*derivative should be in the numerator).

Thanks & Regards

Jitender Singh

IIT Delhi

askIITians Faculty