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M
MBuck21-Visitor
1-Visitor
March 17, 2013
Question

Infinitesimal difference in t i.e. dt

  • March 17, 2013
  • 1 reply
  • 2177 views

I am playing around with the symbolic engine in Mathcad Prime 2. Although my need is trivial (and can be done by visual inspection) despite this I cannot find a way to instruct Mathcad to do it. What I need is a way to insert an infinitesimal difference operator into an equation and multiply it by the differential operator. I accept that I may have overlooked something that others may find obvious but nevertheless I cannot achieve it. What I want to do is to multiply each side of the the following equation by "dt" and then integrate each side to find the function. The integration part is also trivial but the multiplication part escapes me. If there is an obvious work-around pray tell.

This is the example need:

1 reply

A
AlanStevens19-Tanzanite
19-Tanzanite
March 17, 2013

Do you mean like the following (using the Operator and Symbolic menus):

Integrations.PNG

If so, don't forget an arbitrary constant when you equate the two.

Alan

M
MBuck21-VisitorAuthor
1-Visitor
March 17, 2013

Alan

Unless my algebra is incorrect, I agree that if one multiplies by dt on the left you get K*dt but on the right of the equation the integration variable should be dF(t) and not dt. If that so? However, Mathcad will not accept this. The only alternative that I see is substituting F for F(t) and performing the integration but I believe that is not equivalent. But why can I not get Mathcad to do the algebra for me? How can I multiply by dt on both sides of the equation using the symbolic engine.?

Thanks Mark

A
AlanStevens19-Tanzanite
19-Tanzanite
March 17, 2013

You mean like this:

Integrals.PNG

Mathcad treats d/dt as a single operator, not as d(something) divided by dt, so to integrate anything you need to use the integration operator. Mathcad doesn't understand dt on its own.

Alan

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