hi do anyone knows what ∞ - ln∞ gives?

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- October 31st 2010, 04:36 AMfirebrendanswer of ∞ - ln∞
hi do anyone knows what ∞ - ln∞ gives?

[IMG]file:///C:/Users/Arwin/AppData/Local/Temp/msohtmlclip1/01/clip_image002.gif[/IMG][IMG]file:///C:/Users/Arwin/AppData/Local/Temp/msohtmlclip1/01/clip_image002.gif[/IMG] - October 31st 2010, 04:41 AMScurmicurv
It gives infinity. ln∞ does tend to infinity, but not very fast.

Keep in mind though, that infinity isn't like any ordinary number. ∞+∞ = ∞, for example. - October 31st 2010, 04:45 AMmr fantastic
- October 31st 2010, 05:21 AMHallsofIvy
doesn't give anything. "Infinity" is not a real number and ordinary functions such as "logarithm" and "subtraction" do not apply to it. There are extended number systems in which "infinity" is defined as a number but they still do not apply "logarithm" or "subtraction" in the usual sense.

Something of the form lim [f(x)- ln(g(x))] where and may exist but the limit will depend upon exactly**how**f and g "go to infinity".

Quote:

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- October 31st 2010, 06:38 AMfirebrend
The question is:

given: f(x)= x-3/2 ln〖(x^2+2) 〗

Using mathematical arguments, investigate what happens to f(x) as x -> ∞ - October 31st 2010, 07:02 AMProve It

as .

Since the derivative tends to a positive number, the function will continue to increase without bound.

So . - October 31st 2010, 08:31 AMSoroban
Hello, firebrend!

Here is a reallysolution . . .*sloppy*

Quote:

We have: .

For very large

Then: .

It can be shown that: .