MATLAB: Substitute multiple values to array of expressions

arrayequationMATLABsubssymbolicvariable

I have the following code that forms 4 symbolic equations (xs1, xs2, xs3, xs4) using 4 symbolic variables (x1, x2, x3, x4). Problem is, I cannot substitute numeric values into the equations. 
A=[9,1,1,1;1,8,1,1;1,1,7,1;1,1,1,6];
B=[75;54;43;34];
x=sym('x',[1 4]);
xs=sym('xs',[1 4]);
xs(1:4)=0;
for i=1:4
	for j=1:4
		if(j==i)
			continue
		end
		xs(i)=xs(i)-x(j);
	end
	xs(i)=1/A(i,i)*(B(i)+xs(i));
end
What I tried,
x(1:4)=0;
subs(xs);
%another one
subs(xs(1),{x(1),x(2),x(3),x(4)},{[0,0,0,0]})
None worked. How do I do this?

Best Answer

The ‘x’ values are not ‘x1’, ‘x2’, ..., but ‘x(1)’, ‘x(2)’, ...
Try this instead: 
q = subs(xs(1),{x(1),x(2),x(3),x(4)},{[0,0,0,0]});
(Asssign it to whatever variable name you want.)
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