Question

The area(in $\text{sq.units}$) of the region between the curve $y=a\sin x(a>0),x$-axis when $0\le x\le \pi ,$ is

• A. $a$
• B. $2a$
• C. $a^2$
• D. $\frac{a}{2}$

Answer 1

The correct option is B $2a$

Area of $y=a\sin x$ between $x=0$ to $x=\pi$
$=a\times \left(\text{area of}\sin x\text{between}x=0\text{to}x=\pi \right)$
$=a\underset{0}{\overset{\pi }{\int }}\sin xdx=a{[-\cos x]}_0^{\pi }=-a[-1-1]=2a$