TI-85 Program: Calculating Summations

This program for the TI-85 calculates the summation

a(m) + a(m+1) + ... + a(n-1) + a(n) .
To run the program one must input a(i) (the program is written using i as the variable of summation), then the lower limit m, and finally the upper limit n.

For example,to determine the sum

27 + 28 + 29 + 210 + 211
you could input 2 ^ i for a(i), 7 for m, and 11 for n. The same result is also obtained by entering
sum   seq( 2 ^ i, i, 7, 11, 1) .
You also might note that entering 2 ^ (i+7) for a(i), 0 for m, and 4 for n, would be another way to compute the same sum. 

:InpSt "a(i)= ",AI
:St>Eq(AI,A)
:Input "m= ",M
:Input "n= ",N
:sum seq(evalF(A,i,J),J,M,N,1)->S
:Disp "the sum is ", S
:Stop

[In the code typed above, the symbols "St>Eq(" and "evalF(" can be found on the CATALOG menu. The symbol "->" is accessed using the "STO>" key, which is the second key from the lefthand bottom of the calculator. Many of the other command words can be found on the I/O and CTL menus.] 





This document was created on August 31, 1998.

Your questions, comments or suggestions are welcomed. Please direct correspondence to:

Andy Miller
Department of Mathematics
University of Oklahoma
e-mail: amiller@ou.edu

URL: http://www.math.ou.edu/~amiller/ti85/summ.htm