i.3.3.24 Definite Integrals

Condition: Calculate definite integrals: a) \( \int_{\frac{1}{3}}^{\frac{2}{3}} \frac{d x}{\sqrt{4-9 x^{2}}} \) b) \( \int_{0}^{\frac{\pi}{2}} e^{\sin x} \cos x d x \) c) \( \int_{-1}^{1} \tan x d x \), d) \( \int_{0}^{\pi} x^{3} \sin x d x \).