h(x)= integral from (1, 1/x) arctan(2t)dt

Question

part 1: let U= 1/x and du= ?

-> using u=1/x, we can write h(x)= integral from (1, 1/x) arctan (2t)dt as h(u)= integral from (1,u) arctan(2t)dt and h'(u)= arctan (2)

Part 2: By the chain Rule, for functions h(u) and u(x), we have:

-> dh/dx= ______ du/dx