Hello people

I have been trying for hours to find the reduction formulae for this integrations with futility. Help would be hugely appreciated.

I am at a loss when trying to integrate these expressions by parts. While I decrease the degree of one part, the degree of another part increases so I am held impasse.

I need advise on integration by parts, especially on these types of sums.

Here are the problems:

(a)

(b)

The solutions:

(a)

(b)

Please help me