I am REALLY not very good at this because I was away when they were teacher it at school and so I really need to brush up on this but anyway here are a few questions and could someone please help out I'd really appreciate it

Differentiate:

a) x^2 sin (-x)I'm sorry there are many questions here but I really don't know how to do these that well and I was away when they taught it at school

b) sin^2 x

c) cosx.tan 3x

d) x/tan x

e) x^3 - 2 sin (x/3)