MATLAB: How to calculate the coefficients in equations

coefficients

Hello,

Sorry if my question is too basic. I just started using MALTAB and I was wondering how can I solve these four coefficients (a-d) with the following four equations:

1) 20=(13a)*((0.2)^b)*((34)^c)*((0.2)^d)

2) 33=(12a)*((0.32)^b)*((34)^c)*((0.2)^d)

3) 12=(9a)*((0.32)^b)*((34)^c)*((0.1)^d)

4) 20=(13a)*((0.2)^b)*((34)^c)*((0.2)^d)

Thanks !

Best Answer

I would start by taking the log of each of these equations, which will give you linear equations in (a,b,c,d).

Then I would follow one of the techniques for solving linear system discussed on this documentation page.

However, I also notice that your equation (1) and (4) are the same, so it looks like you have an underdetermined system.

Related Solutions

MATLAB: Solving four equations with four unknowns in MATLAB

When you ask a question, it help that you add sufficient information for someone to know your problem without a guess. What did it do that you felt was wrong? If an error message was generated, then show the complete message.

I might point out that fragments like 34.78R1 are not valid syntax in MATLAB. Multiplication employs the * operator.

Beyond that, it seems clear that your equations form a linear system once they are logged. Since you have 4 equations in 4 unknowns, a linear system will yield an exact answer. So backslash would trivially suffice.

MATLAB: Differential and Integral System

Set

y5=intg(y1-y3)
y6=intg(y2-y4)

Then your system becomes

(1) y1'+a*(y1-y3)=0
(2) y2'+b*(y2-y4)=0
(3) y5 + c*y3- d*(y3*y4)=0
(4) y6 + c*y4- e*(y3*y4)=0
(5) y5'=y1-y3
(6) y6'=y2-y4

Use equations (3) and (4) to solve for y3 and y4.

Best wishes

Torsten.

Best Answer

Related Solutions

MATLAB: Solving four equations with four unknowns in MATLAB

MATLAB: Differential and Integral System

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