# Thread: Intergration Help!

1. ## Intergration Help!

Question:
Find the value of the infinite integral:

$\int^\infty_2 \frac{6}{x^4}dx$

Attempt:
$\int^\infty_2 \frac{6}{x^4}dx$
$= 6x^-4$
$= \frac{6x^{-4+1}}{-4+1}$
$= \frac{6x^{-3}}{-3}$
$= -2x^{-3}$
$= [ -2x^{-3} ]^{\infty}_2$
$= [-2(\infty)^{-3} ] - [-2(2)^{-3} ]$
$= ?$

If there was a number in the infinity position then I would be able to solve it, but with the infinity there. I need help!

2. $\mathop {\lim }\limits_{x \to \infty } \frac{1}
{{x^3 }} = 0$

Limit (mathematics) - Wikipedia, the free encyclopedia

3. I didn't understand anything from wikipedia. Can you please explain?

4. Have you studied limits?

5. No, thats the problem. I missed the class