Should I learn chain/product/quotient rules for C2?

It depends on your Exam Board, if you are on AQA, having learned these differentiation methods will not help you in C2, only basic Integration and Differentiation will be asked.

I've learnt differentiation and it's alright but would it allowed to use these to find derivatives in the C2 exam?

+1

It depends on the exam board, but yes if there's differentiation in C2

In general, you can use any techniques learnt in earlier modules to solve problems in a given module. This isn't always the case with applied modules.

For example, I remember when I did FP2, we used the partial fractions method from C4 to prove summation formulae using "the difference of two squares".

Im on MEI.
Yea i learnt partial fractions for method of differences, we do it on FP1. We also do graphs of rational functions, so the quotient rule would be pretty cool to find stationary points.

Yeah, that's what I meant to write, but I accidentally wrote 'the difference of two squares' lol

If only maths so easy lol. Degree-level stuff is tougher (I'm a 1st year ).

You call yourself Dr.A but your profile says you are 18. Can you please explain?

What a peculiar question. I don't suppose Dr Dre ever submitted a doctoral thesis and I'm pretty sure Doctor Who didn't qualify from medical school.