Reply
Wed 10 Nov, 2004 12:39 am
Edit [Moderator]: Moved from General to Science & Mathematics.
I am introducing myself, good lookin female -- double major for BS in physics and BA in technical theatre with math minor -- freaking out over calculus ineptitude and jealous of the only 2 people in my class who actually "get it". check out my webpage if you want to get to know me Edit (Moderator): Link removed I Just need some reasurance or correction for two problems that use L'hospital's Rule.
1. The lim as x->infinity of (1 + a/x) to the power bx.
I managed to get lim of (a(bsquared))/ (1 +a/x) = + infinity with some implicit differentiation and I could be totally wrong but at some point I need to get the right answer into the form e but I am having a brain cramp or something and I can't find it anywhere I was thinking the answer was e to the x power but I have a feeling it can't be that easy and there are more terms floating around that need to be included in the e form.
2. So when proving this: The lim as x-> infinity for (lnx)/(x to the power p) = 0
It is because when we use L'hospital's rule we get eventually lim (1/x)/(P!)
Right? but where do I go from here to get to prove that for any p>0 that the logarithmic function approaches infinity more slowly than any power of x. Do I need to do L'hospital's again and if I do what is the logarithmic form I'm supposed to sub in to get back into a form where the lim of the function is determinate one and is zero?
You would probably have more luck with this butterfryby if you put it in the mathematics section. Welcome
If your are sure that for sufficiently large w
e^(pw) > (1+pw+(1/2)p^2w^2)
for p>0, then you can prove your assertion 2 without recoursing to the L'hospital's rule.
Thanks
I eventually got the answer and the right one for a change and it was a bit less confusing. Thanks for the effort though. I just wish my mathematical side of my brain would decide to kick in before 2 a.m. Now that that's done I wish everyone a happy Veteran's Day and wish myself a good day to study for a physics test.
It seems to me as if you're in the wrong set of fields...
The limit is not zero!
The answer to this is e^AB. I put the details in another post in the mathmatics section, but I hope you don't put zero on your test!
Quote:for p>0, then you can prove your assertion 2 without recoursing to the L'hospital's rule
I do believe it's L'Hopital's rule. Without the s. Apart from that I've done only done calculus in school and haven't started university yet so I can't make any further comments.
"Done only done"?
I'm sure you all realise I meant "only done."
Anyway