The area of the region bounded by the curve $y^2=4 x$ and the line $y=x$ is

The area of the region bounded by the curve $y^2=4 x$ and the line $y=x$ is
  1. $\frac{8}{3}$ sq. units
  2. $\frac{5}{8}$ sq. units
  3. $\frac{3}{8}$ sq. units
  4. $\frac{3}{5}$ sq. units

Solution

Refer figure, point of intersection of given curves are $\mathrm{x}^2=4 \mathrm{x}$ $\Rightarrow \mathrm{x}(\mathrm{x}-4)=0$ $\therefore \mathrm{O} \equiv(0,0) \text { and } \mathrm{P} \equiv(4,4)$ Required area is shaded. $\begin{aligned} & \therefore A=\int_0^4(\sqrt{4 x}-x) d x=2 \int_0^4 x^{\frac{1}{2}} d x-\int_0^4 x d x \\ & =2\left[\frac{x^{\frac{3}{2}}}{\left(\frac{3}{2}\right)}\right]_0^4-\left[\frac{x^2}{2}\right]_0^4-\left(\frac{4}{3}\right)(4 \times 2)-\frac{16}{2} \\ & =\frac{32}{3}-\frac{16}{2}=\frac{16}{6}=\frac{8}{3} \text { sq. units. } \end{aligned}$

Asked in: MHT CET 2021 (21 Sep Shift 1)

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