cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Showing results for 
Search instead for 
Did you mean: 

Community Tip - You can Bookmark boards, posts or articles that you'd like to access again easily! X

Plotting local max-min-points ?

lvl107
20-Turquoise

Plotting local max-min-points ?

  Hello Everyone.

  From :

1.PNG

       Plotting local max-min-points ?

           Thanks in advance.

                 Regards.

1 ACCEPTED SOLUTION

Accepted Solutions
Werner_E
24-Ruby V
(To:lvl107)


@lvl107 wrote:

Could you attach *.xmcd ? ( I'm afraid I may hit wrong key stroke... )

    Best Regards. 


Hmm, really!??

Here's a slightly different approach:

B.PNG

Unfortunately the more direct and logical

B2.PNG

does not work in Mathcad - muPad is not capable to find the solutions.

View solution in original post

9 REPLIES 9

Hi,

 

Set a function that is the derivative of f(x).

Use the root function on this derivative within a range to determine unique roots.

 

You now have enough info to plot the points.

 

Capture.JPG

May be like thif-x.png

lvl107
20-Turquoise
(To:ValeryOchkov)

Many thanks both of you, Valery.Smiley HappySmiley HappySmiley Happy And I still have a query : "How to prove what point is local min-point ?

2.PNG

Best Regards.

Werner_E
24-Ruby V
(To:lvl107)

 

B.PNG

 

lvl107
20-Turquoise
(To:Werner_E)

Could you attach *.xmcd ? ( I'm afraid I may hit wrong key stroke... )

    Best Regards. 

Fred_Kohlhepp
23-Emerald I
(To:lvl107)

AWWW!  C'mon!

Werner_E
24-Ruby V
(To:lvl107)


@lvl107 wrote:

Could you attach *.xmcd ? ( I'm afraid I may hit wrong key stroke... )

    Best Regards. 


Hmm, really!??

Here's a slightly different approach:

B.PNG

Unfortunately the more direct and logical

B2.PNG

does not work in Mathcad - muPad is not capable to find the solutions.

Fred_Kohlhepp
23-Emerald I
(To:lvl107)

Some basic calculus (see Werner's application):

  • First derivatives of a function are zero at inflection points (maxima/minima),
  • The sign of the second derivative at the inflection point indicates minima (second derivative positive) or maxima (second derivative negative.)
Werner_E
24-Ruby V
(To:lvl107)

In case of this function Mathcads symbolics is capable enough to give you al solutions, so you should use it.

If your goal is to limit the results to x1<x<x2 you may use the "assume" modifier.

B.PNG

Top Tags