# RSUM for the Texas Instruments TI 82:

To enter the program, select 'PRGM', 'NEW'. When 'Name =' appears, type in 'RSUM', thenpress the 'ENTER' key. When you have finished typing in the program, press '2^{nd} QUIT'. To run the program, select 'PGRM', 'EXEC', with 'RSUM'highlighted.

**PLEASE NOTE:** 'Disp', 'Input', 'Lbl', 'Goto', and 'IS >' must be entered fromthe 'PGRM' menus; 'Y_{1}' must be entered from the '2^{nd} Y-vars' menu; '' is entered by pressing the 'STO>' key; and all text, label andvariable names are typed in from 'ALPHA' mode. Everything else is entered as a singlekeystroke on the calculator (for example, '+' is entered by pressing the '+' key).

## The program:

To use the program, enter the integrand into the graphing variable Y_{1},available by pressing the 'y=' key. For example, to evaluate , first enter Y_{1}=X^{3}; thenexecute RSUM, with X-min: 1, X-max: 3, and # of subs.: 100.

*Check: *The approximation to that uses 100 sub-intervals ('subs') should produce the output:

LH Sum: 19.7408

RH Sum: 20.2608

Trap. Sum: 20.0008

DONE

(jac) Lastrevised: December 03, 1998