Plot derivative of an ABS( function ) fails (RESOLVED)
04-27-2015, 12:29 PM (This post was last modified: 04-28-2015 04:07 PM by StephanP.)
Post: #1
 StephanP Member Posts: 69 Joined: Apr 2015
Plot derivative of an ABS( function ) fails (RESOLVED)
While testing the HP Prime I ran into the following odd behaviour.

Symb
F1(X)=|X^2 -10X +21| (between absolute brackets)
F2(X)=dF1(X)/dX=X (the derivative of F1)

Plot
F1 plots fine, bouncing nicely at x=3 and x=7
F2 does not plot well. It gives three horizontal line segments.
Y=1 for x < 3
Y=-1 for 3 < x < 7
Y=1 for x > 7 If I use the function Slope in the plot windows, then correct slope values are given for F1.
For F2, slope values are "NaN".

When I remove the absolute brackets from F1, F2 plots perfectly.
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 Messages In This Thread Plot derivative of an ABS( function ) fails (RESOLVED) - StephanP - 04-27-2015 12:29 PM RE: Plot derivative of an ABS( function ) fails - StephanP - 04-28-2015, 12:25 PM RE: Plot derivative of an ABS( function ) fails - rprosperi - 04-28-2015, 01:28 PM RE: Plot derivative of an ABS( function ) fails - ww63 - 04-28-2015, 01:58 PM RE: Plot derivative of an ABS( function ) fails - CR Haeger - 04-28-2015, 02:19 PM RE: Plot derivative of an ABS( function ) fails - Tim Wessman - 04-28-2015, 02:27 PM RE: Plot derivative of an ABS( function ) fails - StephanP - 04-28-2015, 03:58 PM RE: Plot derivative of an ABS( function ) fails (RESOLVED) - Tim Wessman - 04-28-2015, 04:45 PM RE: Plot derivative of an ABS( function ) fails (RESOLVED) - CR Haeger - 04-28-2015, 04:54 PM