Skip to Main Content

Celestial Mechanics on a Graphing Calculator

5. The TI-82 programs

This column used 4 programs written in the TI version of BASIC. They should be easily convertible to any other form of that language. In these programs the list L1 acts like the 4-component vector (x,y,v,w). The windows are adjustable inside the programs, and are set for initial conditions similar to those used in the column. The input L1 must be given as a list inside curly brackets {}. The other inputs requested are B the stopping time, N the number of steps, or M the maximum velocity rotation tolerance, as appropriate. In RK-ADAPT the sine of the angle between the old velocity vector and the new is compared with the tolerance. The three programs EULER4, RK and RK-ADAPT all use the program KSUB as subroutine.