如何在python中用pyqtgraph找函数e^(-cosqx/x^2)的驻点

您可以使用sympy库中的solve函数进行求解。以下是代码示例：

import numpy as np
import pyqtgraph as pg
from sympy import *

# 定义函数
x, q = symbols('x q')
f = exp(-cos(q*x) / x**2)

# 求导数
df = diff(f, x)

# 求解方程 df = 0
res = solve(df, x)

# 转化为numpy数组
res = np.array(res)

# 绘制函数和驻点
x_vals = np.linspace(-10, 10, 500)
y_vals = lambdify(x, f)(x_vals)
pg.plot(x_vals, y_vals, pen='b')

pg.plot(res, [lambdify(x, f)(res)], pen=None, symbol='o', symbolBrush='r', symbolSize=10)

这样就能找到函数e^(-cosqx/x^2)的驻点了。