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20 ' 機械運動学　両てこ機構アニメーションプログラム T.Oku
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40 SCREEN 3:CLS 3
50 XO=230:YO=100:Z=30
60 SC=0:SP=1:N=1
70 PI=3.14159#
80 FOR R=1 TO 360 STEP .6#
90 T=R*PI/180
100 A=5.7#:B=1.2:C=5.8#:D=1.7#
110 AA=(D-B*COS(T))/(B*SIN(T))
120 BB=(B^2-A^2-D^2+C^2)/(2*B*SIN(T))
130 HAN=(2*AA*BB-2*D)^2-4*(1+AA^2)*(BB^2+D^2-C^2)
140 IF HAN<0 THEN 150 ELSE 160
150 PRINT "計算できません.":END
160 X1=(-(2*AA*BB-2*D)+SQR(HAN))/(2*(1+AA^2))
170 X2=(-(2*AA*BB-2*D)-SQR(HAN))/(2*(1+AA^2))
180 Y1=AA*X1+BB
190 Y2=AA*X2+BB
200 IF Y1<Y2 THEN 210 ELSE 220
210 Y=Y2:X=X2:GOTO 230
220 Y=Y1:X=X1
230 AX=X-B*COS(T):AY=Y-B*SIN(T)
240 BX=X:BY=Y
250 SC=N MOD 2:DP=1+((N+1) MOD 2)*16
260 SCREEN ,,SC,DP
270 LINE (XO,YO)-(XO+D*Z,YO),7
280 LINE (XO,YO)-(XO+AX*Z,YO+AY*Z)
290 LINE (XO+AX*Z,YO+AY*Z)-(XO+BX*Z,YO+BY*Z),7
300 LINE (XO+BX*Z,YO+BY*Z)-(XO+D*Z,YO),7
310 CIRCLE (XO,YO),5,5
320 CIRCLE (XO+D*Z,YO),5,5
330 CIRCLE (XO+AX*Z,YO+AY*Z),5,5
340 CIRCLE (XO+BX*Z,YO+BY*Z),5,5
350 SC2=(N+1) MOD 2:DP2=1+((N) MOD 2)*16
360 SCREEN ,,SC2,DP2
370 CLS 3
380 N=N+1
390 NEXT R
400 GOTO 80