Skip to main content
1-Visitor
December 3, 2022
Solved

No solution for variable solve

  • December 3, 2022
  • 2 replies
  • 2997 views

Hello,

 

Can someone tell me why Mathcad isn't able to solve this simple variable? This command works everytime but with these types of equation it doesn't:

 

SP_10515404_0-1670086426394.png

 

I have tried other commands but it still doesn't work:

 

SP_10515404_1-1670086455757.png

 

 

The solution is quite simple, but I would like it to do it automatically:

 

SP_10515404_2-1670086594419.png

 

 

Can somebody help me? Sorry if there are mistakes in my english. Thank you.

 

Best answer by Werner_E

Hmm, one more example of  the "new"  symbolic engine which was introduced with Prime 6 having quite some flaws and being inferior compared to the old one (muPad), which in turn was far away from being perfect or even competitive with Maple or Mathematica.


You may consider reporting this bug to PTC support.

 

Prime 6 is the only version where we still could switch back to the old symbolic engine which finds the solution(s) with ease:

Werner_E_0-1670089752387.png

EDIT: I notice that I have a typo and the 5000 should be 5600

 

But it seems that you are just looking for a numeric result anyway, so why not use one of Primes numeric methods for solving an equation.

Either an ugly looking solve block or the "root" command in one of its two flavors:

Werner_E_1-1670089855341.png

 

BTW, a question to the community: Can anyone explain this error message which I get with a guess value larger than 0.5?

Werner_E_2-1670090090162.png

Looks like the algorithm tries values for x smaller than 10^-62, but why would he do so?

 

 

 

2 replies

24-Ruby III
December 3, 2022

Please upload your Mathcad Prime worksheet here.

The_husk1-VisitorAuthor
1-Visitor
December 3, 2022
24-Ruby III
December 3, 2022

1. What version of the program are you using?
2. Here is the result in version 7.0:

 

Pic_1.png

Werner_E25-Diamond IAnswer
25-Diamond I
December 3, 2022

Hmm, one more example of  the "new"  symbolic engine which was introduced with Prime 6 having quite some flaws and being inferior compared to the old one (muPad), which in turn was far away from being perfect or even competitive with Maple or Mathematica.


You may consider reporting this bug to PTC support.

 

Prime 6 is the only version where we still could switch back to the old symbolic engine which finds the solution(s) with ease:

Werner_E_0-1670089752387.png

EDIT: I notice that I have a typo and the 5000 should be 5600

 

But it seems that you are just looking for a numeric result anyway, so why not use one of Primes numeric methods for solving an equation.

Either an ugly looking solve block or the "root" command in one of its two flavors:

Werner_E_1-1670089855341.png

 

BTW, a question to the community: Can anyone explain this error message which I get with a guess value larger than 0.5?

Werner_E_2-1670090090162.png

Looks like the algorithm tries values for x smaller than 10^-62, but why would he do so?

 

 

 

The_husk1-VisitorAuthor
1-Visitor
December 3, 2022

I tried changing the 'calculation options' and it worked. Thank you.

 

The_husk_0-1670094045694.png