JEE MAIN - Mathematics (2022 - 27th July Evening Shift - No. 7)
The area of the region enclosed by $$y \leq 4 x^{2}, x^{2} \leq 9 y$$ and $$y \leq 4$$, is equal to :
$$\frac{40}{3}$$
$$\frac{56}{3}$$
$$\frac{112}{3}$$
$$\frac{80}{3}$$
Explanation
$$y \le 4{x^2},\,{x^2} \le 9y,\,y \le 4$$
So, required area
$$A = 2\int_0^4 {\left( {3\sqrt y - {1 \over 2}\sqrt y } \right)dy} $$
$$ = 2\,.\,{5 \over 2}\,\,\,\,\,\,\,\,\left[ {{2 \over 3}{y^{{3 \over 2}}}} \right]_0^4$$
$$ = {{10} \over 3}\,\,\,\,\,\,\,\,\,\,\left[ {{4^{{3 \over 2}}} - 0} \right] = {{80} \over 3}$$
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