Вопрос 3. Вычислить: $$ \int_{0}^{\pi} (x^2 + \sin x) dx $$
Найдем интеграл:
$$ \int_{0}^{\pi} (x^2 + \sin x) dx = \int_{0}^{\pi} x^2 dx + \int_{0}^{\pi} \sin x dx $$
$$ \int_{0}^{\pi} x^2 dx = \frac{x^3}{3} \Big|_0^{\pi} = \frac{\pi^3}{3} - \frac{0^3}{3} = \frac{\pi^3}{3} $$
$$ \int_{0}^{\pi} \sin x dx = -\cos x \Big|_0^{\pi} = -\cos(\pi) - (-\cos(0)) = -(-1) - (-1) = 1 + 1 = 2 $$
Сложим результаты:
$$ \int_{0}^{\pi} (x^2 + \sin x) dx = \frac{\pi^3}{3} + 2 $$
Ответ:$$\frac{\pi^3}{3} + 2$$