Skip to main content
1-Visitor
April 4, 2016
Solved

"simple" derivation

  • April 4, 2016
  • 1 reply
  • 1758 views

Hi,

I’m trying a simple derivation with mathcad 15. At least I thought it was easy.

The function is

I want Mathcad to calculate

But the outcome is obviously missing a term…

Check the attachment for the corresponding xmcd or png.

Can somebody tell me what’s wrong?

Michael

Best answer by Werner_E

> Can somebody tell me what’s wrong?

Yes, Mathcad is often very (too) tolerant in this respect, but its wrong from a mathematical point of view to use the same variable for limit AND integration variable as you had done. Use different variables and all works OK.

Mathcads behavior nevertheless is wrong - it should throw an error message instead of yielding a wrong result.

WE

1 reply

Werner_E25-Diamond IAnswer
25-Diamond I
April 4, 2016

> Can somebody tell me what’s wrong?

Yes, Mathcad is often very (too) tolerant in this respect, but its wrong from a mathematical point of view to use the same variable for limit AND integration variable as you had done. Use different variables and all works OK.

Mathcads behavior nevertheless is wrong - it should throw an error message instead of yielding a wrong result.

WE

1-Visitor
April 5, 2016

Thank you for the quick (and good) answer!