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+--- Thread: Incorrect extremum (/thread-6192.html)
Incorrect extremum - lrdheat - 05-01-2016 09:21 PM
On calculator with 10077, I plotted X+ Cos X
When choosing extremum on the graph plot, it incorrectly identifies inflection points where f'(X) , f''(X) both =0 as extremums.
RE: Incorrect extremum - lrdheat - 05-01-2016 10:02 PM
I think you plotted X+1, not X + COS X
RE: Incorrect extremum - Ernesto_R - 05-01-2016 10:31 PM
Hi Spybot!
Your calculator must be in radian mode to plot the graph correctly.
RE: Incorrect extremum - informach - 05-02-2016 02:06 AM
Hi!, Spybot:
In one point, of coordinates, not have minimum and maximum, in extremum (indicated with cross), in the plot image.
Kind Regards.
informach.
RE: Incorrect extremum - lrdheat - 05-02-2016 03:11 AM
Hello informs have and spybot,
On informach's plot, it shows no maximum or minimum found...on my Prime and on my iPad emulator, the inflection points are incorrectly found as extremums.
Why am I getting the results misanalyzed on my units?
RE: Incorrect extremum - lrdheat - 05-02-2016 03:13 AM
Spell correct demolished informach's handle! Sorry about that!
RE: Incorrect extremum - informach - 05-02-2016 12:36 PM
Hi!, Irdheat:
For your knowledge ...
Kind Regards.
RE: Incorrect extremum - retoa - 05-02-2016 01:23 PM
(05-01-2016 09:21 PM)lrdheat Wrote: On calculator with 10077, I plotted X+ Cos X
When choosing extremum on the graph plot, it incorrectly identifies inflection points where f'(X) , f''(X) both =0 as extremums.
You are right, but I don't find it bad, as there is no menu function to find the inflection points.
Extremum will find both extrema and inflection points.
RE: Incorrect extremum - lrdheat - 05-02-2016 03:07 PM
I disagree...an inflection should not be analyzed as an extremum. If an inflection is suspected, one can plot in the advanced graphing app, check for inflection, and confirm with second derivative.
RE: Incorrect extremum - Tim Wessman - 05-02-2016 04:21 PM
Its kind of a legacy from the older HP root finder. You'll notice that the 50G behaves in an identical way. It is definitely something that we'd like to change or improve at some point though because it can be confusing as pointed out.