Evaluate:$\displaystyle \int_{0}^{3} x \cos(\pi x) \, dx$
Find:$\displaystyle \int \dfrac{dx}{\sin x + \sin 2x}$
Evaluate:\[ I = \int_2^4 \left( |x - 2| + |x - 3| + |x - 4| \right) dx \]
Find:\[ \int \frac{dx}{(x + 2)(x^2 + 1)} \]