i.3.3.32 Definite Integrals

condition: Find definite integrals. 1) \( \int_{0}^{\pi / 2} \frac{d x}{3+\cos x} \); 2) \( \int_{0}^{1}(2 x+1) e^{x+2} d x \); 3) \( \int_{0}^{1} \frac{d x}{e^{x}+2} \).