參數(shù)方程曲線繪制用ParametricPlot函數(shù).y[x_] := x + 9.81/2*x*x;k = 1;X[x_] := x - k*y'[x]/(1 + (y'[x])^2)^0.5;Y[x_] := y[x] + k/(1 + (y'[x])^2)^0.5;ParametricPlot[{X[x], Y[x]}, {x, 0, 2}, AspectRatio->1...ClearAll["Global`*"] y[x_] := x*x; x[x_] := x; k = 1; X[x_] := x - k*y'[x]/(1 + (y'[x])^2)^0.5 Y[x_] := y[x] + k/(1 + (y'[x])^2)^0.5 ParametricPlot[{{X[x], Y[x]}, {y[x], x[x]}}, {x, 0, 2}] plot里面給定x的范圍是0-2，但是顯示的不是這個范圍？Plot[{{X[x], Y[x]}, {y[x], x[x]}}, {x, 0, 2}]，結(jié)果出來3條線？請再幫忙看看，謝謝y[t_] := t*t;x[t_] := t;k = 1;X[t_] := t - k*y'[t]/(1 + (y'[t])^2)^0.5;Y[t_] := y[t] + k/(1 + (y'[t])^2)^0.5;ParametricPlot[{{X[t], Y[t]}, {x[t], y[t]}}, {t, 0, 2}]我改了下形參,以免參數(shù)x和函數(shù)x可能會沖突.另,ParametricPlot要X軸寫在前面Y軸寫在后面.你再試試看?