10 COM I,A[37,61],B,E[3],P,P4,A$[10],D[19,2],R1 20 REM PROGRAM NAME = ORB2, PLOTS ORBITS FOR KEP1, KEP2, ORBECC 30 REM JEFFERSON COUNTY WRITING TEAM, LAKEWOOD, COLORADO 40 REM 9 AUGUST 1973 50 GOTO 80 60 CHAIN "$KEP1" 70 CHAIN "$KEP2" 80 DIM V[72],B$[20] 90 Z=240 100 PRINT 110 PRINT "----- PLOT OF ORBIT(S):" 120 PRINT 130 FOR Z=I TO 37 140 N=I-I 150 FOR W=I TO 61 160 IF A[Z,W] THEN 200 170 NEXT W 180 IF NOT N THEN 350 190 GOTO 230 200 N=N+I 210 V[N]=W 220 GOTO 170 230 FOR P=I TO N 240 W=V[P] 250 IF A[Z,W]=I THEN 280 260 IF A[Z,W]=2 THEN 300 270 GOTO 320 280 E$="*" 290 GOTO 330 300 E$="." 310 GOTO 330 320 E$="@" 330 PRINT TAB(V[P]-I);E$; 340 NEXT P 350 PRINT 360 NEXT Z 370 GOTO P4+I OF 380,580,610 380 PRINT "DO YOU WANT TO RUN THIS PROGRAM AGAIN? "; 390 ENTER Z,D,B$ 400 PRINT '13 410 IF B$="YES" THEN 520 420 IF B$#"NO" THEN 380 430 PRINT "DO YOU KNOW HOW TO CALCULATE THE ECCENTRICITY OF AN ORBIT? "; 440 ENTER Z,D,B$ 450 PRINT '13 460 IF B$="YES" THEN 540 470 IF B$#"NO" THEN 430 480 PRINT "TO LEARN HOW, REFER TO THE WORKSHEET FOR KEP1, OR TO" 490 PRINT "SECTION 6-2 OF THE BOOK," 500 GOSUB 640 510 END 520 A$="2" 530 GOTO 60 540 PRINT "THE PROGRAM ORBECC, DISCUSSED IN SECTION 6-3 OF THE BOOK," 550 GOSUB 640 560 PRINT "PLOTS ORBITS FOR WHICH YOU CAN CALCULATE THE ECCENTRICITY." 570 END 580 PRINT "USING THIS PLOTTED ORBIT, 1) LOCATE THE FOCI, AND" 590 PRINT "2) CALCULATE THE ECCENTRICITY." 600 END 610 A$="3" 620 GOTO 70 630 END 640 PRINT " INTERACTIVE METHODS FOR TEACHING SELECTED TOPICS" 650 PRINT " IN HIGH SCHOOL PHYSICS AND MATHEMATICS USING A COMPUTER" 660 RETURN 670 END