# Math Help - Intergration....

1. ## Intergration....

Intergrate....

1. x + 2x^3 divided by (x^4 + x^2)^3 dx

and

2. sin^2 u divided by 1 + cos u du

please help....

2. Originally Posted by sweetchocolat113
Intergrate....

1. x + 2x^3 divided by (x^4 + x^2)^3 dx

and

2. sin^2 u divided by 1 + cos u du

please help....
for the first let $u=x^4+x^2 \mbox{ then } du=(4x^3+2x)dx=2(x+2x^3)dx$

for number 2)

multiply by the conjugate of the denominator

$\int \frac{\sin^2(u)}{1+\cos(u)}\cdot \frac{1-\cos(u)}{1-\cos(u)}du=\int 1- \cos(u)du$