在python中绘制expnential的导数-知道我做错了什么吗？

import numpy as np
import matplotlib.pyplot as plt

def exponential(x):
    return np.exp(x)

def derivative(x, h):
    return (exponential(x + h) - exponential(x)) / h

x = np.linspace(-5, 5, 100)
h = 0.001
y = derivative(x, h)

plt.plot(x, y)
plt.xlabel('x')
plt.ylabel("Derivative of exponential")
plt.title("Plot of the derivative of exponential function")
plt.show()

import sympy as sp
import matplotlib.pyplot as plt

x = sp.symbols('x')
y = sp.exp(x)
dy = sp.diff(y, x)

f = sp.lambdify(x, dy, 'numpy')
x_vals = np.linspace(-5, 5, 100)
y_vals = f(x_vals)

plt.plot(x_vals, y_vals)
plt.xlabel('x')
plt.ylabel("Derivative of exponential")
plt.title("Plot of the derivative of exponential function")
plt.show()