Extremum graphing question
12-11-2016, 05:39 PM
Post: #1
 lrdheat Senior Member Posts: 614 Joined: Feb 2014
Extremum graphing question
On a graph of abs(cos X), is there a way for the graphing app function analysis to recognize minimum extremums? The app only recognizes maximums...seems to have difficulty with such a function defined at all X values that have a clear minimum f(X), but no defined f'(X) at those points.

Is it possible for the graphing app to be designed to find these extremums?
12-12-2016, 12:47 AM
Post: #2
 lrdheat Senior Member Posts: 614 Joined: Feb 2014
RE: Extremum graphing question
In graph app for abs(cos X), root does succeed where extremum fails in finding a value approximating a root (and labels it as an extremum!), but even this would fail if, instead, the function was abs(cos X) + 1.

Could the graphing app be designed to have success with these sorts of functions?
12-12-2016, 07:22 AM
Post: #3
 cyrille de brébisson Senior Member Posts: 1,047 Joined: Dec 2013
RE: Extremum graphing question
Hello,

The failure is due to the fact that the calculator derivates and then tries to find a 0 of the derivative to find extremums. Since the derivative of abs is not defined in 0, it fails to find the 0.

Cyrille

Although I work for the HP calculator group, the views and opinions I post here are my own. I do not speak for HP.
12-12-2016, 11:52 AM
Post: #4
 Jan_D Member Posts: 69 Joined: Nov 2016
RE: Extremum graphing question
The Advanced Graphing app finds the minima.
In Numeric View choose: Trace – PoI –Vertical Extrema.

It finds a minimum function value of 1.52655665886E-16, but it could be worse!
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