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J
jsuarez1-Visitor
1-Visitor
October 18, 2015
Question

graphing inequalities in mathcad and shading an are of interest

  • October 18, 2015
  • 22 replies
  • 8712 views

Is it possible graphing inequalities in mathcad and shading an area of interest in the graph?

Example

graph these inequalities and shade the are that found at the interception points

y<=3-(x/4)

y<=6-x

y>=1

x>=2

thank you!

juan.

22 replies

V
ValeryOchkov24-Ruby IV
24-Ruby IV
October 19, 2015

First step

xxyy.png

F
Fred_Kohlhepp23-Emerald I
23-Emerald I
October 19, 2015

You can bound and "shade" in version 15 (with a little imagination).

Might be able to get creative in Prime; bounding is the same, shading would be a larger challenge.

PS:  posting multiple times will get you a LOT of complaints and no more real help.

V
ValeryOchkov24-Ruby IV
24-Ruby IV
October 19, 2015

xy.png

W
Werner_E25-Diamond I
25-Diamond I
October 19, 2015

Here is another approach using a 3D contourplot in Mathcad 15.

Guess you could change the colors using a custom color map.

    V
    ValeryOchkov24-Ruby IV
    24-Ruby IV
    October 19, 2015

    Werner Exinger wrote:

    Here is another approach using a 3D contourplot in Mathcad 15.

    Fine, Werner, but sorry the counter plot  is not 3D plot.

    W
    Werner_E25-Diamond I
    25-Diamond I
    October 19, 2015

    Valery Ochkov wrote:

    Werner Exinger wrote:

    Here is another approach using a 3D contourplot in Mathcad 15.

    Fine, Werner, but sorry the counter plot  is not 3D plot.

    Why?

    Its the projection of a 3-dimensional surface in a 2-dimensional plane of projection. Its an orthographic projection, in German sometimes also called "Kotierte Projektion" (was not able to find an English expression for it, Googles "listed projection" sure is wrong).

    Its not the same as a plan view, but quite similar.

    So its the same situation as with an isometric or any perspective view of an object. They, too, are projections from 3-dimensional space to 2-dimensional space.

    So if a contour plot does not apply as 3D-plot in your eyes, neither of the others like surface plot or scatter plot should apply a well as they all result in a 2D-picture of a 3D situation.

    So in your eyes Mathcad is not be capable of doing 3D-plots because it does not create sculptures, because its not a 3D printer? Or because it does not create data for the Oculus Rift?

    So for me, the 3D in 3D-plot does not refer to the output (which of course is 2D) but to the input and so a contour plot certainly is a 3D plot as well.

    Werner

    A
    AlvaroDíaz12-Amethyst
    12-Amethyst
    October 20, 2015

    Simple brute force surface filling. Can be improved a lot, but is very effective. Topology is hard, so, following examples have not holes. Also, can extract the border (asking for abs(XY) < TOL or something else better). This is some sort of equivalent of differentiate functions. The notations is similar to: dR = Border(R). Well, partial d, can't found greeks here. ORIGIN =1.

    Best regards.

    FillR.gif

    PD: Can't type this in Prime, sorry.

    V
    ValeryOchkov24-Ruby IV
    24-Ruby IV
    October 20, 2015

    Alvaro,

    create please with the Simple brute Method this 2D plot for 2015/10/31

    H.png

      A
      AlvaroDíaz12-Amethyst
      12-Amethyst
      October 20, 2015

      Ok. But in my country we don't celebrate with that. We celebrate Día de muertos. And only in november 2. (Others take more seriously the question and take nov 1 too).

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