i.3.1.54 Indefinite integrals

Condition: Find the indefinite integrals: 1) \( \int \frac{e^{2 x}-2 e^{x}}{e^{2 x}+1} d x \), 2) \( \int \arcsin x d x \) 3) \( \int\left(x^{2}+1\right) 3^{x} d x \) \( \int \frac{x^{3}-2 x^{2}-12 x-7}{x^{3}-3 x-2} d x \).