How can I try and solve this differentiation, I don`t understand it?

Well how much do you understand about it? Have you got any ideas at the moment?
(Then I would work through the multi-staged question with them)
1) What equation do you use to work out these type of answers? (Lead them to simple differential formula) (Help them apply it)2)Explain my understanding of stationary coordinates, plus simply how to identify them. (Work through the question with them, giving hints if necessary)3)Explain my understanding of second order differential equations, and how you can tackle this question. Talk about key words to identify what to do.
(I found an example question that I used to base my answer about, given why each sub question refers to a different part of differentiation )