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1-Newbie

## Use Mathcad 2001i to reproduce this simple chart

Hi,

I studied Maths at Uni over 10 years ago and during that time we were given a copy of Mathcad2001i.

I am now writing up an assignment for another uni course and would like to include a simple chart. I would like to produce this chart using Mathcad 2001i but its been so long since I last used Mathcad I have no idea what im doing!

Please could someone help me reproduce this figure in Mathcad so that I dont have to use a scanned facsimile.

I just want to repreodcue what is seen in the attached image.

Thank you!

6 REPLIES 6
24-Ruby V
(To:rpotts)

You sure would hav eto provide more information. What you showed may be the vector field plot of an aordinary first order differential equation, maybe something like y'=x*y. We can do this in Mathcad, Vector Field Plot is a special 3D plot type. Including one solution curve is tricky to do in 3D, you would have to plot a cylinder which has the solution as base curve and the generating lines parallel to the z-axis. I have posted something like this here in the forum a long time ago, but with a quick search I wasn't able to find that post. It too long ago I used MC2001 (never had 2001i) ao I also don't know about what features 2001i had and which were implemented later, but I guess Vector Field Plots was available.

You might also be interested in a document I once posted - it deals with vector field plots as 2D plots (and of course it wouldn't be difficult to do it without arrows. http://communities.ptc.com/docs/DOC-3503

Unfortunately I can't save in the format of your version, so if you are interested you either have to find someone who is able to do the conversion (has a MC14/15 and a version 11 installed) or you are willing to retype it (a pdf is included there, so you can see how its done).

24-Ruby V
(To:rpotts)

Here is an approach using a modification of the vector field plots routine (again MC14/15; therefore pdf included))

1-Newbie
(To:rpotts)

Thank you so much for your replies!

I am doing a simple 3rd year assignment on population viability analysis and have started with an introduction to lotka-volterra equations. 'Yes', it is a direction field of a first order differential. (x'=kx). I want to include this direction field when I describe exponential growth of a single population, ie before interaction.

Ill have to re-read both posts and have a play around but I have enough info now to re-produce the field I scanned in my OP.

Thank you once again! I can now hand in the assignment without an ugly scanned copy from a book!

24-Ruby V
(To:rpotts)

You are welcome! In case you need a sheet created with a newer Mathcad version you may consider asking in this forum if someone could convert it for you to 2001i format. Some regular posters here have different versions of MC installed and are able to do so.

In my last sheet I mistakenly interchanged x and t when defining D1 as I am used to x being abscissa! It didn't matter as the function was symmetrical in t and x, but yours is not.

1-Newbie
(To:Werner_E)

Thank you!

I obvioulsy couldnt open the .xmcdz files that you uploaded and, in honesty, struggled to enter the script from the .pdf to Mathcad2001i so I downloaded the Mathcad 15 demo and had a play around.

My end result is this...

The assignement is finally ready to hand in!

24-Ruby V
(To:rpotts)
 struggled to enter the script from the .pdf to Mathcad2001i

That was the reason I suggested you ask here for someone to do the conversion, but of course the eval version does the job as well.

Glad you found what you searched.

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