Problem 24

Question

Use integration tables to evaluate the integral. $$ \int_{0}^{\pi} x \sin x d x $$

Step-by-Step Solution

Verified
Answer
The evaluated definite integral is \(\pi\).
1Step 1: Identify the Method to Use
Recognize that the integral is a product of a linear function and a sine function, thus integration by parts will be used. The formula for integration by parts, found in integration tables, is \( \int u dv = uv - \int v du \).This formula will be applied with \(u = x, dv = sin(x) dx\).
2Step 2: Compute the Derivative and the Integral
Calculate the derivative of u, \( du = dx \), and calculate the integral of \( dv, v = -cos(x) \).
3Step 3: Apply the Integration by Parts Formula
The integral becomes \( -x \cdot cos(x) - (- \int cos(x) dx) \). Evaluate the integral inside the parentheses, which gives \( sin(x) \), leading to \( -x \cdot cos(x) + sin(x) \).
4Step 4: Evaluate the Definite Integral
Substitute the limits of integration, from 0 to pi, to find the definite integral by calculating \(-\pi cos(\pi) + sin(\pi) - (0 - 0)\) which simplifies to \(-\pi \cdot -1 - 0 = \pi\).