Breaking a function into components?

I have a function containing several variables which I am looking to pull from it the individual variables and their values. i.e. function =5x+3y+8z. I need to be able to extract from this, say just the x variable and its value, answer=5x. Thanks in advance

Answer 1

[Star Strider]

You probably need to use the Symbolic Math Toolbox, especially if you have only one such equation. (The Symbolic Math Toolbox doesn’t work efficiently for iterative calculations.)

syms x y z
f = 5*x+3*y+8*z
% Set  y=0 and z=0 (then simplify if necessary): 
f1 = subs(f, {y,z},{0,0})

yields:

f1 =

5*x

[Chris]

Thanks a heap, thats done the trick.

[Star Strider]

My pleasure!

Answer 2

[George Papazafeiropoulos]

Make a function named myfunc as follows:

%----------------------

function out=myfunc(a,vec)

out=a.*vec;

end

%----------------------

Then run the following code:

a=[5;3;8];

x=1;

y=2;

z=3;

vec=[x;y;z];

out=myfunc(a,vec)

I hope this is what you want...

[Chris]

Cheers George, not quite what i was looking for but I've got my answer now.