I am stumped as to how to approach this one:

Prove that the remainder term in Taylor's theorem can be replaced by

$\displaystyle R_{n}(x)=\frac{1}{n!}\int^x_a f^{(n+1)}(t)(x-t)^ndt$ provided that $\displaystyle f^{(n+1)}$ is Riemann integrable.

[Taylors remainder term: $\displaystyle R_n(x)=\frac{f^{(n+1)}(c)}{(n+1)!}(x-a)^{n+1}$