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Forum URL: http://www.cut-the-knot.org/cgi-bin/dcforum/forumctk.cgi
Forum Name: College math
Topic ID: 261
#0, Calculus (Limits)
Posted by Riddhi on May-06-02 at 09:35 PM
I am in a dire need for you to answer this Limits question from Calculus. I would greatly appreciate anybody's constructive help ~ I would be really grateful.

Use lim (h -> 0) for (f(x+h) - f(x))/(h)

to solve the function:

f(x) = x ^ (2/3)

I would be soooo incredibly happy if you can answer this question! Thanks.

~ Riddhi.


#1, RE: Calculus (Limits)
Posted by anshoo on May-07-02 at 01:53 PM
In response to message #0
use the following binomial expansion:

(x+h)^n = x^n + (x^(n-1))*n*h + (x^(n-2))*(n(n-1)/2!)*h^2 + ....

note that the above expansion holds true even if n is a fraction!


#2, RE: Calculus (Limits)
Posted by Michael Klipper on Jul-27-02 at 02:45 PM
In response to message #0
Solve the function for WHAT? For values where f(x) = 0? For a simplified version?

If you're looking for a root, x = 0 is the only root.

If you're looking for a different representation, then the answer given before me does work. Beware, though, that this representation goes on infinitely.