Re: Absolute Value Differentiation

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Posted by Mary on October 03, 2002 at 20:41:59:

In Reply to: Re: Absolute Value Differentiation posted by Jack on October 03, 2002 at 20:13:51:

: : Hi,

: : How would I go about finding "for which values of X is the absolute value function y = abs x differentiate?"
: :
: : I am not sure either. But, if you plot y=abs(x) you get two lines, y=-x and y=+x. y=-x has a derivative over the range -infinity: : I'm not sure where to begin. Perhaps I've forgotten too much about absolute values....

: : Please help. Thanks!

I found the formula for it, but I don't understand it.

y(x) = |x|
|x| = sqrt x^2
x/dx |x| = d/dx *2sqrt(x^2)
x/ |x|

Therefore
1 if x >0
-1 if x <0

Does that make sense to you? I can't make sense of it.

Follow Ups:

Re: Absolute Value Differentiation Adam Getchell 00:51:53 10/04/02 (2)
- you all are really making this too difficult... T.Gracken 07:50:18 10/04/02 (1)
  - Re: you all are really making this too difficult... Adam Getchell 04:00:19 10/13/02 (0)

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: : : Hi, : : : How would I go about finding "for which values of X is the absolute value function y = abs x differentiate?" : : : : : : I am not sure either. But, if you plot y=abs(x) you get two lines, y=-x and y=+x. y=-x has a derivative over the range -infinity<x<0 and y=x has a derivative over the range 0<x<+infinity. : : : I'm not sure where to begin. Perhaps I've forgotten too much about absolute values.... : : : Please help. Thanks! : : I found the formula for it, but I don't understand it. : y(x) = |x| : |x| = sqrt x^2 : x/dx |x| = d/dx *2sqrt(x^2) : x/ |x| : Therefore : 1 if x >0 : -1 if x <0 : Does that make sense to you? I can't make sense of it.

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