I want to plot a discrete function in mathematica like, for example, the following: X=[X1,x2,X3]and Y = {1 if X<=X1,20 if X1< X<=X1+X2,40 if X1+X2< X<=X1+X2+X3}
In addition I would like to use the Manipulate code to be able how the step function moves if I change the values X1,X2 or X3.
Thanks a lot for your help!