getting an equation from multiple variables

I need to get the equation of a multiple variables. I have the data a matrix of 5 coulomns; one coloumn for the output and the others for the variables.

Did anyone use a function to get the equation parameters?

[Bob Thompson]

I don't understand what you're asking for. Are you wanting to try and figure out the function based on the inputs and output? Or are you wanting to generate the output for a known equation using the four inputs?

[Essam Ali]

I want to get the equation as y=5x+3y+z-3W something like that.

[James Tursa]

Are you trying to fit a curve to some data? E.g., linear regression?

[Essam Ali]

not curve but an output of experimental results from variables.

[Bob Thompson]

Something like:

out = 5*(variables(:,1))+3*(variables(:,2))+variables(:,3)-3*(variables(:,4));

[Essam Ali]

No. IF I have two variables affecting third one. as example power=Voltage*current.If I have a matrix of Third coloumns for different readings of power, voltage and current but I don't know the equation(power=Voltage*current), how can I get the unknown equation?

[James Tursa]

There is no magic method for determining a formula from arbitrary data. Typically you would have some idea about what the data represents and get a formula from that. Then plotting and trying various fits to see how well it matches expectations for residuals, etc.

[Essam Ali]

Polyfit function does this but in one variable

[Walter Roberson]

file exchange has polyfitn

Answer 1

[madhan ravi]

MAtrix = [3, 6, 1, 3, 8; 3, 6, 1, 3, 9];
syms x y z w Out
Out * MAtrix(:, 1) == (MAtrix(:, 2 : end) * [x, y, z, w].') % something like this?

ans = 

[Essam Ali]

no these are two differenr equations.