Let f be integrable on [a,b] and let c be a point in that interval. Define
F=∫acf(x)dxandG=∫cbf(x)dx.
(a) Express ∫baf(x)dx in terms of F and G.
(b) Prove that F+G=∫abf(x)dx for all real numbers a,b, and c with a≤c≤b or b≤c≤a.
(c) For real numbers a1,a2,…,an with ak+1=ak and an+1=a1, prove that
k=1∑n∫ak+1akf(x)dx=0.