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Anousheh1-Visitor
1-Visitor
February 10, 2013
Solved

Symbolic Derivative Problem

  • February 10, 2013
  • 1 reply
  • 4055 views

Hello,

Please see the attached worksheet.

I need the actual derivative of vf(lambda,alpha) function. MathCad says it is too long to be shown.

Is there any way to overcome this issue?

Thank you so much.

Anousheh

Best answer by Werner_E

Anousheh Rouzbehani schrieb:

Hello,

Please see the attached worksheet.

I need the actual derivative of vf(lambda,alpha) function. MathCad says it is too long to be shown.

Where? I couldn't find that problem in you worksheet. Obviously I'm missing the point. Always better to post a stripped down worksheets which just shows the error or, as in your case, the undesired behaviour.

As you have defined Alpha at the top I assume you are interested in the derivative wrt lamda. I move the range variable for lamda down a bit.

cohesive2.png

One way to look at an expression which Mathcad 15 says being to long is to convert the worksheet in Prime format and load it in Prime 2, if you have the possibility to do so. Prime would let you scroll - no, unfortunately not, but you are allowed to enlarge the expression region to the right.

1 reply

W
Werner_E25-Diamond IAnswer
25-Diamond I
February 10, 2013

Anousheh Rouzbehani schrieb:

Hello,

Please see the attached worksheet.

I need the actual derivative of vf(lambda,alpha) function. MathCad says it is too long to be shown.

Where? I couldn't find that problem in you worksheet. Obviously I'm missing the point. Always better to post a stripped down worksheets which just shows the error or, as in your case, the undesired behaviour.

As you have defined Alpha at the top I assume you are interested in the derivative wrt lamda. I move the range variable for lamda down a bit.

cohesive2.png

One way to look at an expression which Mathcad 15 says being to long is to convert the worksheet in Prime format and load it in Prime 2, if you have the possibility to do so. Prime would let you scroll - no, unfortunately not, but you are allowed to enlarge the expression region to the right.

H
HarveyHensley12-Amethyst
12-Amethyst
February 10, 2013

Werner,

I was working on this at the same time. I was able to get the derivative when alpha = .5 as was assumed in the worksheet, but the evaluation doesn't complete in a long time when other values for alpha are used. The same happens with your suggestion for the modifiers. When alpa is treated as a variable without a value, then the long result occurs.

Anousheh showed plots with other values of alpha, so I assume there will be an interest in a more general result. Any ideas?

Harvey

A
Anousheh1-VisitorAuthor
1-Visitor
February 11, 2013

Hi, Thank you Werner.

A few more question. If you don't mind please:

1- What is the different between "simplify" with and without "max"?

2- What is the little black rectangle at the top right corner of some blocks? Is it for not to display the results?

3- At the bottom of the worksheet, I see green border around the first graph (which I suppose means that it is working), but nothing happens. I have good processor and sufficient ram in my computer, so I don't know why it takes so long to settle down. (Still nothing happening!)

4- What do you mean by saying:

Werner Exinger wrote:

To overcome this you would have to turn the solve block in a function.

How do you like my technique of inserting quotes?!

Thank you for your time and help.

Anousheh

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