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graphing inequalities in mathcad and shading an are of interest

jsuarez
1-Newbie

graphing inequalities in mathcad and shading an are of interest

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 22

First step

xxyy.png

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.

xy.png

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

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

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.

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

For me if one object has x & y - it is 2D-object.

If has x,  y & z - it is 3D

One picture from Thermal Engineering studies with Excel, Mathcad and Internet

6-04.png

Both have reason, because are talking about different things. One thing is the object, and another their representation. Peano's curve (the object) fills the plane (the representation). Planes are 2D but Peano's curves are 1D. In other words: an object with 1 degree of freedom can have a representation in 2D, which have 2 degrees of freedom. Reciprocal holds too: Maybe we live in the 2D border of the 3D galaxy as holograms. Problem here is that if it is, the galaxy border is the object, and the galaxy is the representation, and we live in planeland. (Improper planeland, in the argot of the old projective geometry)

Werner:

"Its the projection of a 3-dimensional surface in a 2-dimensional plane of projection" ---- Representation.

Valery:

"For me if one object has x & y - it is 2D-object."   ---- Object


AlvaroDíaz wrote:

Both have reason


There is one joke about this:

"...and you are the wife of the right!"

What you show are two pictures.

Both are projections, 2D-representations, of a 3D-object.

You may either call both a 3D-plot or none of them.

In both there is information missing which you would need to reconstruct the original 3D object. You would need at least two pictures belonging together (like the orthogonal parallel view above and from the front) to be able to reconstruct the object OR some additional information. You can provide that additional information much more easier with the contour plot by numbering the contour lines. That way you could easily reconstruct the original surface with a certain degree of accuracy (we can't provide all contour lines). So the contour plot is closer to the original 3D object than the surface plot, even if the latter is more pleasing and appealing to the layman's eye.

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.

Alvaro,

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

H.png

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).

AlvaroDíaz wrote:

Ok. But in my country we don't celebrate with that.

In Russia we have this day each day of year

It's food. We don't play with food in our neighborhood. It's peccata minuta, but peccata at the end. And ... not! I'm not Dante's wife!!!.

Valery Ochkov wrote:

AlvaroDíaz wrote:

Ok. But in my country we don't celebrate with that.

In Russia we have this day each day of year

How about combining the Russian and Mexican traditions in a Technologically Terrible way and constructing a Death Star in orbit?

Solids with Holes

Stuart

Stuart,

An article "Industrial Pumpkin Carving" in the help: Industrial Pumpkin Carving with Mathematica—Wolfram Blog

StuartBruff
23-Emerald II
(To:VladimirN)

VladimirN. wrote:

Stuart,

An article "Industrial Pumpkin Carving" in the help: Industrial Pumpkin Carving with Mathematica—Wolfram Blog

Surely, Vladimir, this is the ideal PTC project - a Mathcad-derived, Creo 3D drawing set driving a CNC machine to carve out a pumpkin and then attach a 3D-printed set of LED candles, controlled by an Arduino (or Raspberry Pi, as we're on a food theme) linked to a sound card that utters scary things (like "We're withdrawing Mathcad 15 and invalidating all its licences tonight! ")?

Stuart

Jajajaja. You perfect describe lab work at the campuse!!!.

No, thanks Stuart. One thing is draw a calabaza with some few holes in 2D placed somewhere, with a ten lines code procedure. But draw your kill monster with this strange symmetry that is not a symmetry, is too much. Certainly, I'm uruguayan, living in México, that's true. I say. Just in case. Just in case that you want some tequila. Maybe caña, or wine. And nothing of real calabacitas. Those, virtuals only.

AlvaroDíaz wrote:

No, thanks Stuart. One thing is draw a calabaza with some few holes in 2D placed somewhere, with a ten lines code procedure. But draw your kill monster with this strange symmetry that is not a symmetry, is too much. Certainly, I'm uruguayan, living in México, that's true. I say. Just in case. Just in case that you want some tequila. Maybe caña, or wine. And nothing of real calabacitas. Those, virtuals only.

Hmmph.  Spoilsport.

Stuart

Sorry, it was one joke with 2015/10/31

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