Can someone help me?

[ptc-5090961]

Hi, I have a system of 11 equations. I need to find what are values of these 11 variables. For example I brought value 1 and I wanted to see if the system works. It doesn't work and I don't understand why...Maybe I don't know how to make a system of equations in mathcad...Can someone look what's the problem?

[VladimirN]

Hi,

Try to use "Minerr" function instead of "Find".

[Werner_E]

VladimirN. wrote:

Hi,

Try to use "Minerr" function instead of "Find".

Would not help. As there are only two different equations Mathcad would set 9 variables to zero and minimize for the remaining two.

[Werner_E]

You have 11 variables to solve for, but only 2 different equations! You first 9 equations are ident as are the last 2, because you set all coefficients to 1.

[ptc-5090961]

But there must be some answers to system. I will change everything from 1 to another numbers later. But now it doesn't show me any answers.

[ptc-5090961]

I need answers like in this picture (it doesn't matter 1 or other number).

[Werner_E]

Jonas Jonaitis wrote:

I need answers like in this picture (it doesn't matter 1 or other number).

It DOES matter!!!

[Werner_E]

Jonas Jonaitis wrote:

But there must be some answers to system.

Wow, now you have four different equations for 11 variables!

While Mathcad would return at least one solution to an underdetermined system, in case of your system - no, there aren't any solutions! Look at your last two equations. With the coefficients you had chosen you they mean you are searching numbers x1 to x9 with a sum of 2400 and 4260 at the same time - hard to find, don't you think so?

Furthermore this time you forgot to provide guess values!

I will change everything from 1 to another numbers later.

That will be too late!

But now it doesn't show me any answers.

For good reason - Mathcad is correct in doing so, see above.

[ptc-5090961]

Here's a full system of equations. Why it doesn't calculate x1, x1 and etc... ?

[Werner_E]

Provide guess values and Mathcad returns a solution

[ptc-5090961]

Thanks very much for help I didn't know how to provide guess values..

[Werner_E]

Jonas Jonaitis wrote:

Thanks very much for help I didn't know how to provide guess values..

No problem.

BTW, you provided guess values yourself in your very first attachment but you deleted it in the second and third.

Guess values simply are normal assignments to the solve variables at the beginning of a solve block or in front of it. In case of an underdetermined system the guess values may influence which solution Mathcad will arrive to.