Question

Let f(x)=c for all x in [a,b] and some real number c. Show by definition below that f is Riemann integrable on [a,b], and int f(x) dx = c(b-a).

Definition: A function f is Riemann integrable on [a,b] if there is a real number R such that for any epsilon > 0, there exists delta > 0 such that for any a partition P of [a,b] satisfying ||P||< delta, and for any Riemann sum R(f,P) of relative to P, we have |R(f,P)-R|< epsilon