Question

Вычислить интегралы
1,3 пример ​

Answer 1

1.

$\int\limits^{ 1 } _ {0} \frac{dx}{ \sqrt{ {x}^{2} + 2x + 2 } } = \int\limits^{ 1 } _ {0} \frac{dx}{ \sqrt{ {x}^{2} + 2x + 1 + 1 } } = \\ = \int\limits^{ 1 } _ {0} \frac{d(x + 1)}{ \sqrt{ {(x + 1)}^{2} + {1}^{2} } } = ln( |x + 1 + \sqrt{ {x}^{2} + 2x + 1 } | ) | ^{ 1 } _ {0} = \\ = ln(2 + \sqrt{4} ) - ln(1 + 1) = ln( \frac{4}{2} ) = ln(2)$

2.

$\int\limits^{ 1 } _ { - 1} \frac{dx}{1 + {x}^{2} } = arctgx | ^{ 1 } _ { - 1} = arctg(1) - arctg( - 1) = \\ = \frac{\pi}{4} - ( - \frac{\pi}{4} ) = \frac{\pi}{2}$