LertPianapitham

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Solve System of n equations

Forum|Forum|14 years ago
October 14, 2011
3 replies
5791 views

Hello Everybody,

i have a question about Mathcad 14. How can i solve a System of n equations that has all equations in the same form like

Equation i: Q_i = k_i*A_i*DT ....

when DT is a constant, all Q_i and k_i are given.

How can i do this directly? I dont want to write all equations down, coz i want to keep the number of equations as a variable.

Thanks

Lert

Other

Best answer by Fred_Kohlhepp

Solve blocks are amazing things!

23-Emerald I

done

1_n-equations-xmcd.zip

12-Amethyst

Added a function format to Fred's

1_n-equations-1-xmcd.zip

23-Emerald I

Wayne Reid wrote:
Added a function format to Fred's

I thought the idea was to solve for A_i. You can still do what you were doing, just write a different function.

LertPianapitham

5-Regular Member

Author

5-Regular Member

Hi all,

Thx for ur answers. i'm in vacation and will check the files next week.... actually i have another system that's more complicated .... looks like

Equations i:

Q_i = k_i*A_i*DT_i

DT_i = ((T_S - T_E) - (T_S - T_A_i)) / (ln(T_S - T_E) - ln(T_S - T_A_i))

T_A_i = T_E + (Q_i * Sum(A_i)) / (m_K * A_i * C_p)

the Q_i and k_i are given. the T_S, T_E, m_K and C_p are constant. that means ... we have only A_i, DT_i and T_A_i as variables ( 3n Equations ... 3n Variables)

can i use ur technics in those files or how can i do this?

Thx again for both of u.

Lert

Ps. if u cannot understand this, i will create a file next week.

24-Ruby IV

Lert Pianapitham wrote:
Hi all,
Thx for ur answers. i'm in vacation and will check the files next week.... actually i have another system that's more complicated .... looks like
Equations i:
Q_i = k_i*A_i*DT_i
DT_i = ((T_S - T_E) - (T_S - T_A_i)) / (ln(T_S - T_E) - ln(T_S - T_A_i))
T_A_i = T_E + (Q_i * Sum(A_i)) / (m_K * A_i * C_p)
the Q_i and k_i are given. the T_S, T_E, m_K and C_p are constant. that means ... we have only A_i, DT_i and T_A_i as variables ( 3n Equations ... 3n Variables)
can i use ur technics in those files or how can i do this?
Thx again for both of u.
Lert
Ps. if u cannot understand this, i will create a file next week.

Send please this equations as a Mathcad-sheet.

1-Visitor

Hello! I am struggling with solve blocks in MathCAD, trying to make Given-Find too, not working for my equations.

Could you explain how it is working and how I can find solution to my problem?

I have 3 equations, 2 of them have 1 variable each(x and y), 3rd equation is for help...

See attached worksheet.

Many Thanks and Regards,

Aidan

LertPianapitham

5-Regular Member

Author

5-Regular Member

Thx. very much .... it's very useful!

Lert