Question

Обчислити інтеграл виділенням повного квадрату
Допоможіть будь ласка

Answer 1

$\int{\frac{dx}{2x^2-4x+5}} =\int{\frac{dx}{((\sqrt{2}x)^2-4x+(\sqrt{2})^2)+3}} =\int{\frac{dx}{(\sqrt{2}x-\sqrt{2})^2+3}} =\int{\frac{dx}{(\sqrt{2}x-\sqrt{2})^2+(\sqrt{3})^2}} = \\ \\ = \frac{1}{\sqrt{2}}\int{\frac{d(\sqrt{2}x-\sqrt{2})}{(\sqrt{2}x-\sqrt{2})^2+(\sqrt{3})^2}}=\frac{1}{\sqrt{2}}\cdot \frac{1}{\sqrt{3}}arctg \, (\frac{\sqrt{2}x-\sqrt{2}}{\sqrt{3}})+C= \\ \\ = \frac{1}{\sqrt{6}}\cdot arctg \, (\sqrt{\frac{2}{3}}\cdot(x-1))+C=\frac{\sqrt{6}}{6}\cdot arctg \, (\sqrt{\frac{2}{3}}\cdot(x-1))+C$