How to Integrate [1/(x^2 + 1)] dx? | Physics Forums - The Fusion of Science and Community
OK, as you asked for it: FIRST u = x^2 + 1, du/dx = 2x, du/2x = dx [tex]\int\frac{1}{x^2+1} \ dx = \int\frac{1}{u} \ \frac{du}{2x}[/tex] I can not do further because the x variable is still exist. SECOND [tex]x = tan \ \...