REM trochoid
let a=1
let b=0.8
SET WINDOW -0.2,7,-1,6
DRAW axes
DEF f(t)=a*t-b*SIN(t)
DEF g(t)=a*1-b*COS(t)
LET h=0.05
SET LINE COLOR 2
FOR t=0 TO 10-h STEP h 
   PLOT LINES:f(t),g(t);f(t+h),g(t+h)
   WAIT DELAY 0.01
NEXT t
END
----------------------------------------
REM epitrochoid 曲線
LET a=1
LET b=1/5
LET b1=0.8*b
SET WINDOW -1.2*(a+2*b),1.2*(a+2*b),-1.2*(a+2*b),1.2*(a+2*b)
LET h=0.01
DEF f(t)=(a+b)*COS(t)-b1*COS((a+b)/b*t)
DEF g(t)=(a+b)*SIN(t)-b1*SIN((a+b)/b*t)
DRAW axes
SET LINE COLOR 4
DRAW circle WITH SCALE(a)
SET LINE COLOR 2
FOR t=0 TO 4*PI-h STEP h
   PLOT LINES:f(t),g(t);f(t+h),g(t+h)
   WAIT DELAY 0.01
NEXT t
END
----------------------------------------
REM hypotrochoid 曲線
LET a=1
LET b=2/5
LET b1=0.8*b
SET WINDOW -1.2*a,1.2*a,-1.2*a,1.2*a
LET h=0.01
DEF f(t)=(a-b)*COS(t)+b1*COS((a-b)/b*t)
DEF g(t)=(a-b)*SIN(t)-b1*SIN((a-b)/b*t)
DRAW axes
SET LINE COLOR 4
DRAW circle WITH SCALE(a)
SET LINE COLOR 2
FOR t=0 TO 4*PI-h STEP h
   PLOT LINES:f(t),g(t);f(t+h),g(t+h)
   WAIT DELAY 0.01
NEXT t
END
-------------------------------------------
REM 円の伸開線
LET a=1
SET WINDOW -15*a,15*a,-15*a,15*a
DRAW axes
SET LINE COLOR 4
DRAW circle
DEF f(t)=a*COS(t)+a*t*SIN(t)
DEF g(t)=a*SIN(t)-a*t*COS(t)
LET h=0.05
SET LINE COLOR 2
FOR t=0 TO 4*PI-h STEP h 
   PLOT LINES:f(t),g(t);f(t+h),g(t+h)
   WAIT DELAY 0.01
NEXT t
END
-------------------------------------------
REM アルキメデスの螺線
LET a=1
SET WINDOW -13*a,13*a,-13*a,13*a
DRAW axes
DEF f(t)=a*t
LET h=0.05
SET LINE COLOR 2
FOR t=0 TO 4*PI-h STEP h 
   PLOT LINES:f(t)*COS(t),f(t)*SIN(t);f(t+h)*COS(t+h),f(t+h)*SIN(t+h)
   WAIT DELAY 0.01
NEXT t
END
-------------------------------------
REM 等角螺線，対数螺線
LET a=1.2
SET WINDOW -13*a,13*a,-13*a,13*a
DRAW axes
DEF f(t)=a^t
LET h=0.05
SET LINE COLOR 2
FOR t=0 TO 4*PI-h STEP h 
   PLOT LINES:f(t)*COS(t),f(t)*SIN(t);f(t+h)*COS(t+h),f(t+h)*SIN(t+h)
   WAIT DELAY 0.01
NEXT t
END
---------------------------------------------------
REM 正葉線
LET a=1
LET n=10
SET WINDOW -1.3*a,1.3*a,-1.3*a,1.3*a
DRAW axes
DEF f(t)=a*SIN(n*t)
LET h=0.01
SET LINE COLOR 2
FOR t=0 TO 2*PI-h STEP h 
   PLOT LINES:f(t)*COS(t),f(t)*SIN(t);f(t+h)*COS(t+h),f(t+h)*SIN(t+h)
   WAIT DELAY 0.01
NEXT t
END
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