MATLAB: Symsum undefined function error

symsum

I am trying to plot an equation with an infinite series using symsum.
I get this error when I try to plot it.
>> plot(x,.9-symsum((2./(n*3.14159)).*(sin(.1*n*3.14159))*(exp(-(n.^2)*(3.14159.^2)*x)),n,1,Inf));
Undefined function 'symsum' for input arguments of type 'double'.
Based on previous questions I thought it might be a problem of having the toolbox but that is in the right directory. Maybe I can't use symsum with my argument type, but is there another function I can use? Sum also didn't work (I got: Error using sum Dimension argument must be a positive integer scalar within indexing range.)

Best Answer

First you need to
syms n