Introduction Functions  Environments:-  J  Matlab Mathematica Maple APL HP48G TI85 TI89
Function definitions on the TI-85
PROGRAM: SAMPLE 
 :Prompt xMin 
 :Prompt xMax 
 :Prompt N 
 :Disp ''X= (STO to rename)''
 :seq( x, x, xMin, xMax, (xMax-xMin)/N ) ® X 

 PROGRAM: D 
 :Ans ® zx 
 :dimL zx ® zn 
 :zn-1 ® dimL zy 
 :For (i,1,zn-1) 
 :zx(i+1) - zx(i) ® zy(i) 
 :End 
 :zy 

 PROGRAM: MIDS 
 :Ans ® zx 
 :dimL zx ® zn 
 :zn-1 ® dimL zy 
 :For (i,1,zn-1) 
 :(zx(i) + zx(i+1))/ 2 ® zy(i) 
 :End 
 :zy 

 PROGRAM: S 
 :Ans ® zx 
 :dimL zx ® zn 
 :zn+1 ® dimL zy 
 :0 ® zy(1) 
 :For (i,1,zn) 
 :zy(i) + zx(i) ® zy(i+1) 
 :End 
 :zy

This Texas Instruments calculator performs list manipulations and plotting. The notations DY/DX and sum(YM*DX) can be directly entered, using the intrinsic sum operation (on the 2nd LIST OPS menu). All arithmetic and scientific functions on lists are applied to each element, for example 
   EXP(-X)*SIN(X^2+2*X+3) ®
will operate on list X and define list Y. Other operations can't use such nice notation since they involve calling user-defined programs that operate on the previous result. For example 
   X: D: Ans ® DX and 
   YM*DX: S: Ans ® SY 
can each be entered on one line including colons. Alternatively use ENTER instead of colon and STO for Ans ®

The programs use for loops and three 'temporary' variables zx, zy and zn
To plot lists Y vs X, enter: xyline X,Y   The RANGE is determined in the GRAPH menu options. To superimpose curves, do not CLDRW (clear the drawing) between plots. 

Zooming, or any scale change, is not very easy, since changing a RANGE parameter will clear the screen and then you must recreate the curves with xyline

 [Readers with browsers displaying fonts different from ours should note that  ® is intended to be a right pointing arrow.]
Introduction Functions Environments:-  J  Matlab Mathematica Maple APL HP48G TI85 TI89