I want to plot three cumulative normal distributions. I know the parameters mu and sigma from each function. If I give the commands 

f:=int(1/sqrt(2*Pi)/sigma*exp(-(x-mu)^2/2/sigma^2),x);             1

plot(subs({mu=0,sigma=1},(1)),x=-4..8);

I get a 2d-plot. But I want to illustrate, how functions can be moved in space. In the 2d-plot, the x-axis illustrates the values of the random variable and the y-axis illustrates...