What is the proof for this?

I was learning calculus and it seemed very interesting than Olympiad topics like Algebra, NT, Geometry and Combinatorics.

But I was struck here. I used this relation many times. But I don't know the proof for this. I hovered internet for over four days continuously but can't find it anywhere? Please help me to know the proof for this relation.

Note by Surya Prakash
4 years, 11 months ago

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- 4 years, 11 months ago

Well, I will ask you first what have you tried. Don't forget the definition of digamma and move on with the proof and I think you'll prove it.

- 4 years, 11 months ago

Actually digamma function is defined as

But how can this help to prove digamma function.

- 4 years, 11 months ago

Hey man u r really awesome at calculus. Where can I contact u? I see u r in our hangouts group but u r inactive there.

- 4 years, 11 months ago

I learnt it from here.

- 4 years, 11 months ago