Problem in linsolve , the equation on the left side not accepted

Hi All

I am defining equation as :

M_num = - (19*c2)/4 - (11*c3)/18 - 50 ;

M_n2 = - 7*c2 - (5*c3)/18 - 50 ;

then I have :

 linsolve({M_num = 0, M_n2 = 0}, {c2, c3}) ;

and I get the error :

Error: The expression to the left of the equals sign is not a valid target for an assignment.

WHY ??

Answer 1

[Geoff Hayes]

Farzad - see the documentation for linsolve. If you are trying to solve the system of equations Ax=B, then you need to define your A and B with two unknowns of c2 and c3, then you should try something like

 A = [-19/4 -11/18 ; -7 -5/18];
 B = [50 ; 5];
 X = linsolve(A,B);

[Image Analyst]

farzad's reply moved from being an "Answer" to being a comment:

Thanks Geof , but I was doing according to : here

and you see they wrote the equations directly , ok then , in this case , since I am letting matlab to repalce and produce the equations and then solve them , so I can not intervene in the middle and extract those coefficients to replace here , but is there a way to do this ?

[Geoff Hayes]

Farzad - you are referencing code that is used in the MuPad interface. Is that what you are using?