如何用 Sympy 绘制点？

Question

我需要计算并绘制一个函数，它是前两个导数。然后，我需要在图形上绘制原始函数的最小值和最大值点。我已经计算了这些，但不知道如何绘制数据。最小/最大点的 x 值是 criticalPoints[]

y 值是

criticalPointsY[]

这是出现错误的代码段。

equation=CreateFunction();

    firstDeriv=equation.diff(x);

    secondDeriv=firstDeriv.diff(x);

    print(equation);

criticalPoints=solveset(firstDeriv,x);

criticalPointsY=[];

for a in criticalPoints:

    criticalPointsY.append(equation.subs(x,a));

p=plot(equation,firstDeriv,secondDeriv,(x,-10,10));

# Need to add the critical points to the graph. We have them, and the

# y values, but need to put them on the graphs.

print(criticalPoints)

print(criticalPointsY);

for a in range(0, len(criticalPoints)):

    xval=criticalPoints[a];

    yval=criticalPointsY[a];

    plt.plot(xval, yval, 'ro')

p.show();

plt.show();

当我运行程序时，出现此错误。`

Traceback (most recent call last):

  File "--------", line 58, in <module>

    xval=criticalPoints[a];

TypeError: 'FiniteSet' object does not support indexing

我尝试在 p 上绘制点并得到不同的错误

    p.plot(criticalPoints,criticalPointsY);

AttributeError: 'Plot' object has no attribute 'plot'

有没有办法在这个图上绘制点？(p)