# Homework Help: ((x^2)+1)^2 using substitution

1. Jul 20, 2010

### Sidthewall

1. The problem statement, all variables and given/known data
((x^2)+1)^2 integrate using substitution

2. Relevant equations

3. The attempt at solution
ok so i let u= x^2 + 1
du/dx = 2x
du= 2xdx
where do i go from there

Last edited: Jul 20, 2010
2. Jul 20, 2010

### Staff: Mentor

Do what with ((x^2)+1)^2 using substitution?

3. Jul 20, 2010

### Sidthewall

integrate using substitution, my bad forgot to put that down

4. Jul 20, 2010

### Staff: Mentor

That's the reason for this: 1. The problem statement, all variables and given/known data

So is this it?
$$\int (x^2 + 1)^2 dx$$

I wouldn't use substitution for this one.

5. Jul 20, 2010

### Sidthewall

I wouldn't either. I would expand and then solve but the question said to use substitution

6. Jul 20, 2010

### vela

Staff Emeritus
The substitution u=x2+1 won't help. What substitution does the form x2+1 suggest? Think trig functions.