The area enclosed by the parabola $x^2 = 6y$ and the line $x-6y+2=0$ is: |
$\frac{1}{3}$ $\frac{3}{8}$ $\frac{1}{2}$ $\frac{3}{4}$ |
$\frac{3}{4}$ |
$x^2 = 6y$ ...(1) $x - 6y+2=0$ $⇒6y=x+2$ ...(2) Placing value of 6y from (2) in (1) $x^2=x+2$ $x^2-x-2=0$ $x^2-2x+x-2=0$ $x(x-2)+1(x-2)=0$ $x=-1,2$ So both intersect at $x=-1$ and $x=2$ area = area under line - area under parabola $⇒\int\limits_{-1}^2\frac{x}{6}+\frac{1}{3}-\frac{x^2}{6}dx$ $[∵x^2=6y⇒y=\frac{x^2}{6},\,6y=x+2=y=\frac{1}{6}x+\frac{1}{3}]$ $=\left[\frac{x^2}{12}+\frac{x}{3}-\frac{x^3}{18}\right]_{-1}^2$ $=\frac{4}{12}+\frac{2}{3}-\frac{8}{18}-\frac{1}{12}+\frac{1}{3}-\frac{1}{18}$ $=\frac{3}{12}+\frac{3}{3}-\frac{9}{18}=\frac{1}{4}-1-\frac{1}{2}=\frac{1}{4}+\frac{1}{2}=\frac{3}{4}$ sq. units |