旋轮线(Cycloid)也叫摆线。一个半径为 a 的圆在x轴上滚动时,圆上一个点的轨迹就是旋轮线。
其中theta是圆所转的角度。
参数方程的推导:
with(plots):a:=1:
curve:=plot([a*(theta-sin(theta)),a*(1-cos(theta)),theta=0..2*Pi],thickness=2):
display(curve,scaling=constrained,tickmarks=[0,0]);
两拱:
with(plots):a:=1:
curve:=plot([a*(theta-sin(theta)),a*(1-cos(theta)),theta=0..4*Pi],thickness=2):
display(curve,scaling=constrained,tickmarks=[0,0]);
动画:
动画的Maple程序:
with(plots): with(plottools):
R:=1:a:=0:b:=4*Pi:
x:=t->R*(t-sin(t)):y:=t->R*(1-cos(t)):
K:=60:for i from 1 to K do ti:=a+i*(b-a)/K:
quxian[i]:=plot([x(t),y(t),t=a..ti]):
yuan[i]:=circle([ti,R],R,color=blue):
xian[i]:=plot([[ti,R],[x(ti),y(ti)]],color=brown):
M[i]:=display(quxian[i],yuan[i],xian[i]) od:
L:=display(seq(M[i],i=1..K),insequence=true):
display(L,L,scaling=constrained,tickmarks=[5,2],thickness=2);
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