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Topic: Does this imply that lim x --> oo f'(x) = 0?
Replies: 18   Last Post: May 26, 2013 1:28 AM

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 Graham Cooper Posts: 4,495 Registered: 5/20/10
Re: Does this imply that lim x --> oo f'(x) = 0?
Posted: May 24, 2013 11:28 PM

On May 25, 12:50 pm, William Elliot <ma...@panix.com> wrote:
> On Fri, 24 May 2013, baclesb...@gmail.com wrote:
> > On Friday, May 24, 2013 3:28:09 AM UTC-4, William Elliot wrote:
> > > > > Suppose f:[0, oo) --> R is increasing, differentiable and has a
> > > > > finite limit as x --> oo. Then, must we have lim x --> oo f'(x) =
> > > > > 0?  I guess not, but couldn't find a counter example.

>
> Give it up, counter examples have been presented.

I think this one works..

-1/(5+sin(x))/x/x

http://www.wolframalpha.com/input/?i=-1%2F%285%2Bsin%28x%29%29%2Fx%2Fx

Herc
--
www.BLoCKPROLOG.com

Date Subject Author
5/23/13 steinerartur@gmail.com
5/23/13 Robin Chapman
5/23/13 David C. Ullrich
5/23/13 Bart Goddard
5/23/13 steinerartur@gmail.com
5/23/13 William Elliot
5/24/13 steinerartur@gmail.com
5/24/13 Bacle H
5/24/13 William Elliot
5/24/13 Bacle H
5/24/13 William Elliot
5/24/13 Graham Cooper
5/24/13 Graham Cooper
5/25/13 steinerartur@gmail.com
5/25/13 Graham Cooper
5/26/13 Bacle H
5/26/13 Bacle H
5/24/13 William Elliot
5/24/13 Graham Cooper