Issues entering probability distrubution function in matlab

Question

I want to enter this function into matlab, but I am in doubt what to do with the infinite spectrum

My try was this, but the graph looks very wrong

Answer 1

As described by @icurays you should use the correct function and range:

x = -25:0.001:25;
f=1/2*(1+(2/pi)*atan(x/5));

Furthermore you will probably want to get your plot in the right position, so not only plot the function values, but also give the x values as input to your plot function:

plot(x,expcdf(f))

I do not have Matlab at hand, so there may be a typo somewhere, but it should work like this.