basic matlab help: mimes inner matrix dimensions must agree

>> R=2.5:0.01:4; >> S=(1+R+(R.^2)/3)*exp(-R); ??? Error using ==> mtimes Inner matrix dimensions must agree.

>> J=exp(-2*R)*(1+R.^-1); ??? Error using ==> mtimes Inner matrix dimensions must agree.

need to plot these for R between 2.5-4

I really don't know how to fix this :(

Answer 1

[Star Strider]

You were close to being successful. You need to use .* to do element-by-element multiplication:

R=2.5:0.01:4; 
S=(1+R+(R.^2)/3).*exp(-R);
J=exp(-2*R).*(1+R.^-1);

That should do what you want. (It at least runs without errors.)

It might be a bit more efficient to write J as:

J = exp(-2*R).*(1+1./R);