Area under the curveMedium

Question

The area of the region $\{(x,y):y \leq \pi - |x|,y \leq \mid xsinx \mid ,y \geq 0\}$ is :

Options

A.$1 + \frac{\pi^{2}}{8}$
B.$2 + \frac{\pi^{2}}{4}$
C.$\frac{\pi^{2}}{8} - 1$
D.$4 + \frac{\pi^{2}}{2}$

Solution

Sol. [Key Concept: Sketch $y = \pi - |x|$ and $y = |xsin\ x|$; integrate the enclosed strips.]

Area ; $2\left( \int_{0}^{\pi/2}\mspace{2mu} xsinxdx + \int_{\pi/2}^{\pi}\mspace{2mu}(\pi - x)dx \right)$

$$\begin{matrix} & \ = 2( - xcosx + sinx)_{0}^{\pi/2} + 2\left( \left. \ \frac{(\pi - x)^{2}}{2} \right|_{\pi}^{\pi/2} \right) \\ & \ = 2 + \frac{\pi^{2}}{4} \end{matrix}$$

Create a free account to view solution

View Solution Free
Topic: Area under the curve·Practice all Area under the curve questions

More Area under the curve Questions