# Thread: got as far as i could in solving integrals by parts, need help at this step

1. ## got as far as i could in solving integrals by parts, need help at this step

I'm doing some integrals by parts here and understand the general theory but have a bit of a slow down when applying the steps.

The scan shows my steps but I'm stuck at 5. I believe I simplified everything correctly but have difficulty moving to the next step, mainly the -2/7 integral xdx part.

2. Originally Posted by solidstatemath
I'm doing some integrals by parts here and understand the general theory but have a bit of a slow down when applying the steps.

The scan shows my steps but I'm stuck at 5. I believe I simplified everything correctly but have difficulty moving to the next step, mainly the -2/7 integral xdx part.
If $u=ln(7x), du=(1/x)$ by way of Chain Rule.

3. If u = ln(x) then du = 1/2 * dx.

Shouldn't it be 1/7x * dx where "7x" is the "x" in the above example?