- #1

UrbanXrisis

- 1,196

- 1

[tex]\int 4(1+x^2)^{-1}[/tex]

[tex]u=1+x^2[/tex]

[tex]du=2x[/tex]

[tex]\frac{2du}{x}=4dx[/tex]

[tex]2\int \frac{u^{-1}}{x} dx[/tex]

[tex]2ln(ux)[/tex]

[tex]=2ln(x+x^3)|_{0}^{1}[/tex]

[tex]=2ln(1+1^3)-2ln(0+0^3)[/tex]

I know I did something wrong, any ideas?