I need to prove:

lim (x^4)-(2(x^2)) = +inf

x->+inf

Any suggestions?

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- Oct 26th 2008, 11:33 AMCalc1stuInfinite Limit Proof
I need to prove:

lim (x^4)-(2(x^2)) = +inf

x->+inf

Any suggestions? - Oct 26th 2008, 11:52 AMflyingsquirrel
Hi,

Hint : - Oct 29th 2008, 12:46 PMCalc1stu
I don't know how to do it. The problem is done and over with, but I still would like to know how to get the answer for my own knowledge.

- Oct 29th 2008, 12:52 PMMathstud28
- Oct 30th 2008, 08:05 AMCalc1stu
It was supposed to be an epsilon delta proof.

- Oct 30th 2008, 09:06 AMo_O
You want to show that for every , there exists such that whenever , it necessarily follows that

Consider the latter expression as an equality:

(since and )

(we're considering positive x's)

So when we have that . We want to show that for some , we have that

Now consider: . Can you finish? - Oct 30th 2008, 11:19 AMCalc1stu
As far as epsilon and delta are concerned which is M and N. I don't know where to go from there. All we ever usually do or did was a basic function.