I have
$\displaystyle \int (3x+1) \sqrt{3x-1}~dx$
$\displaystyle u = 3x-1$
$\displaystyle \frac{du}{du} = 3$
which gives $\displaystyle \frac{1}{3}\int \frac{du}{dx} (u+2)\sqrt{u}~dx = \frac{1}{3}\int (u+2)\sqrt{u}~du $
Is this correct so far?
I have
$\displaystyle \int (3x+1) \sqrt{3x-1}~dx$
$\displaystyle u = 3x-1$
$\displaystyle \frac{du}{du} = 3$
which gives $\displaystyle \frac{1}{3}\int \frac{du}{dx} (u+2)\sqrt{u}~dx = \frac{1}{3}\int (u+2)\sqrt{u}~du $
Is this correct so far?