Introduction
Functions
 Environments:-
 J 
Matlab
Mathematica
Maple
APL
HP48G
TI85
TI89
Function definitions in APL
A typical sequence to demonstrate that the derivative of the integral returns the original function consists of:
    
   x  <- 100 sample 0 3  
   y  <-    exp -x*2   
   Iy  <-  S (mids y) x d x   
   DIy <-  (d Iy)  %   d x   
   plot (y  vs  x) and (DIy vs mids x)   
   
vs is a function that delivers the lists y and x to the plot function in the required form; while function and delivers several tables to plot.
APL*PLUS III workspace, APLMM.w3, may be downloaded for the functions.
[Readers with browsers that do not display the fonts we intended, should note the following equivalences above: 
<-  is a left pointing arrow,  x is the multiplication sign and % is the division sign.]
Introduction
Functions
Environments:-
 J 
Matlab
Mathematica
Maple
APL
HP48G
TI85
TI89