Skip to main content
A
aayyappan1-Visitor
1-Visitor
August 6, 2014
Question

variational method

  • August 6, 2014
  • 3 replies
  • 3237 views

Hello,

I am creating a worksheet for variational method. but have a problem in minimization, pls see the attachment.

3 replies

M
MikeArmstrong1-Visitor
1-Visitor
August 6, 2014

Unless I am going mad, didn't I see a thread created by you today with an integration problem, which seems to have been solved in this new sheet?

A
AlanStevens19-Tanzanite
19-Tanzanite
August 6, 2014

You haven't defined N, so Mathcad thinks it means Newtons. Your definition of Psi has 'a' as an input argument, but the right-hand side of the function doesn't contain 'a' at all (should it be alpha?)! No wonder E(a) gives a single value whatever value is passed to it for 'a'!

Psi also doesn't cater for the situation where z is exactly L/2.

Alan

M
MikeArmstrong1-Visitor
1-Visitor
August 6, 2014

Alan,

I take it that response was meant for Anitha and not me

As I said, the worksheet needs some work

M
MikeArmstrong1-Visitor
1-Visitor
August 6, 2014

Please check your workings. E(a) returns a value of value of 2.478 for all values of a.

Clipboard01.jpg

W
Werner_E25-Diamond I
25-Diamond I
August 6, 2014

N.1 is calculated but never used

Definition of Psi(z,a):

1) Are you sure about N here? N is not defined anywhere so Mathcad assumes you mean the unit Newton. I guess this is not what you intended, as you don't use any units in the rest of your sheet.

2) The argument "a" is never used in the function definition, so Psi is not dependent on "a" and therefore the argument "a" should be omitted, use only Psi(z):=...

E(a): This function does not depend on "a". "a" is never used other than as argument of Psi and its without effect there as said above. So the result of E() is not influenced by "a" and therefore, as Mike had noticed, is the same constant value for any argument provided.

Terms & ConditionsAccessibility statement