Defining the function file for fsolve

function F=nonlinearsolver(x,y) F=[y-x^2-3*x-2; y-2*x-3]; end

This is a function file used to store the system of non linear equation for using with the fsolve. but when ever i called it like this [e,t,exitflag]=fsolve(@nonlinearsolver,[10;10]) it gives errors.

but if i define my function file like this function F=nonlinearsolver(x) F=[x(2)-x(1)^2-3*x(1)-2; x(2)-2*x(1)-3]; end and call the same way as previously it gives right answer. please suggest me the way to rectify the problem associated with the function file or with others.

Answer 1

[Azzi Abdelmalek]

Your function: replace x by x(1) and y by x(2)

function F=nonlinearsolver(x)
F=[x(2)-x(1)^2-3*x(1)-2; x(2)-2*x(1)-3];

%call your function

sol=fsolve(@nonlinearsolver,[10;10])

[farzad]

@Azzi Abdelmalek : so there should not be a tab for the equation line in the function file ? what about the parameters for example ?

I mean , if I have fixed values to insert in the equation , like the coefficient 3. and if it's a global parameter from the main code, does it create a problem ?

[Steven Lord]

FYI farzad asked this question about indentation in the function files in this question so discussion of that should probably take place in that other question.