$\int_{0}^{a} \sqrt{a^{2}-x^{2}} d x$ এর যোজিত ফল কত?

$\frac{\pi \mathrm{a}^{2}}{2}$

$\frac{\pi \mathrm{a}^{2}}{3}$

$\frac{\pi \mathrm{a}^{2}}{4}$

$\pi \mathrm{a}^{2}$