Skip to main content
A
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

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

Your Beta value is OK. But, remember that alpha is an index with the values of 0.5, 0.45 and 0.40

There is nothing wrong with your solve block, I was just getting rid of all which could detract (me).

Didn't look that closely to the rest of your sheet and was just poking around with arbitrary values of alpha.

For publication purposes, I need to have the actual derivative function to be included in the paper.

No problem with specific values of alpha, but with generic alpha - no way with Mathcad, I guess. And even if it would be possible (maybe with Prime) it wouldn't fit in your paper with a readable font size I think.

Terms & ConditionsAccessibility statement