Skip to main content
J
jappelman1-Visitor
1-Visitor
January 6, 2017
Question

Given / Find function not working

  • January 6, 2017
  • 4 replies
  • 6260 views

Dear readers,

I'm having a problem with MathCAD 15 to calculate forces.

I need 15 variabels (Fay Fax Faz, Fby Fbx Fbz, Fcy Fcx Fcz, Fdy Fdx Fdz, Fmmpy Fmmpx Fmmpz) and had 21 formulas. I red somewhere that it had to be 15 formulaes for 15 variables.

So i managed to get rid of 6 formulas.

Still undefined when i try to use the "find" function.

Hope someone can help.

Regards,

Jeroen

4 replies

R
Raiko17-Peridot
17-Peridot
January 6, 2017

Hello,

when using the error tracing tool (Right-click on solution and choose "Trace Error") it says that your variable Rbdx (among others) is not defined. These need to be defined as starting values.

Good luck

Raiko

-
-MFra-21-Topaz II
21-Topaz II
January 6, 2017

Hi Jeroen

are missing some initial guesses

mathcad_daf.jpg

J
jappelman1-VisitorAuthor
1-Visitor
January 6, 2017

Thanks both for the very fast reaction!

I can't work on it right now, probably sunday.

I will check everything like you both said.

Thanks!

J
jappelman1-VisitorAuthor
1-Visitor
January 11, 2017

Still having a lot of problems with the answers.

For now, I Need:

F.mmpy = 190,2558 [N]

F.mmpx = 0 [N]

F.mmpz = 0 [N]

F.ay=F.by=F.cy=F.dy=F.mmpy/4

R.acx=R.bdx=0.05029 [m]

R.ay=R.by=0.378501 [m]

R.cy=R.dy=0.205599 [m]

Can't share my current file in this text..

-
-MFra-21-Topaz II
21-Topaz II
January 12, 2017

Hi Jeroen,

You can get what you want by entering in the Solve Block the conditions to be satisfied by the system.
To have a solution you have to change the initial estimates until you get a solution (which is not easy).
I added after the Solve Block the same equation for verification. See Attachment.
J
jappelman1-VisitorAuthor
1-Visitor
January 18, 2017

I've started all over again because I couldn't get it working correctly.

I hope someone can help me because my deadline is friday...

Regards

V
ValeryOchkov24-Ruby IV
24-Ruby IV
January 18, 2017

1. You have 12 equations and 8 unknowns!

2. Your system is linear. Use please the lsolve function! See please Given/Find and lsolve for one problem here 17.15 and 17.16 here Study 17. Cogeneration (CHP), trigeneration (CCHP) and quadrogeneration (CCHPI) or how much of mathematic is contain…

Terms & ConditionsAccessibility statement