Exercise 1.7.17 (Integration by parts formula)

Let F,G : R R be monotone non-decreasing and continuous. Show that

[a,b]FdG = [a,b]GdF + F(b)G(b) F(a)G(a)

for any compact interval [a,b].

This formula can be partially extended to the case when one or both of F,G have discontinuities, but care must be taken when F and G are simultaneously discontinuous at the same location.