Let be integrable on and let be a point in that interval

MATHEMATICS · Multi-part · A Level · Mathematics · Integration · Integration

Problem

Let ff be integrable on [a,b][a,b] and let cc be a point in that interval. Define F=∫acf(x) dxandG=∫cbf(x) dx.F = \int_{a}^{c} f(x)\,dx \quad \text{and} \quad G = \int_{c}^{b} f(x)\,dx. (a) Express ∫baf(x) dx\displaystyle\int_{b}^{a} f(x)\,dx in terms of FF and GG. (b) Prove that F+G=∫abf(x) dxF+G = \displaystyle\int_{a}^{b} f(x)\,dx for all real numbers a,b,a, b, and cc with a≤c≤ba\le c \le b or b≤c≤ab\le c \le a. (c) For real numbers a1,a2,…,ana_1,a_2,\dots,a_n with ak+1≠aka_{k+1}\ne a_k and an+1=a1a_{n+1}=a_1, prove that ∑k=1n∫ak+1akf(x) dx=0.\sum_{k=1}^{n} \int_{a_{k+1}}^{a_k} f(x)\,dx = 0.

Related theory

Browse the problem library