# Another Integration Question

• Feb 24th 2009, 12:35 PM
gammaman
Another Integration Question
Why is U raised to the -1/5 here in the second step?

I understand that the 4/5 came from bringing u^1/5 up so that -1/5 + 1 = 4/5, but I do not see where the -1/5 comes from.

$\frac{1}{16}\int\frac{u-5}{u^{1/5}}du$
$\frac{1}{16}[u^{{4/5}} - 5u^{{-1/5}}]du$
• Feb 24th 2009, 12:36 PM
Chris L T521
Quote:

Originally Posted by gammaman
Why is U raised to the -1/5 here in the second step?

I understand that the 4/5 came from bringing u^1/5 up so that -1/5 + 1 = 4/5, but I do not see where the -1/5 comes from.

$\frac{1}{16}\int\frac{u-5}{u^{1/5}}du$
$\frac{1}{16}[u^{{4/5}} - 5u^{{-1/5}}]du$

It comes from basic rules of exponents...

$\frac{1}{a^n}=a^{-n}$