Q82 / 170 · Manipal (MET) 2020 · Mathematics
$\lim _{x \rightarrow 0} \frac{\int_0^{x^2} \sin \sqrt{t} d t}{x^3}$ is equal to
- Correct answerA$\frac{2}{3}$
- B$\frac{1}{3}$
- C$0$
- D$\infty$
Solution
$\lim _{x \rightarrow 0} \frac{\int_0^{x^2} \sin \sqrt{t} d t}{x^3} \quad\left(\right.$ form $\left.\frac{0}{0}\right)$
$=\lim _{x \rightarrow 0} \frac{\sin \sqrt{x^2} \times 2 x}{3 x^2}$
(using L' Hospital's rule)
$=\lim _{x \rightarrow 0} \frac{2}{3} \frac{\sin x}{x}=\frac{2}{3} \times 1=\frac{2}{3}$
Hence, the correct answer is option: 'A'.