import matplotlib.pyplot as plt

import numpy as np

def f(x):
    return 4*np.sin(x)

def g(x):
    return x**2

def plot_3d_surface():
    fig = plt.figure()
    ax = fig.add_subplot(111, projection='3d')
    x = np.linspace(-5, 5, 100)
    y = np.linspace(-5, 5, 100)
    X, Y = np.meshgrid(x, y)
    Z = f(X) + g(Y)
    ax.plot_surface(X, Y, Z, cmap='viridis')
    ax.set_xlabel('X-axis')
    ax.set_ylabel('Y-axis')
    ax.set_zlabel('Z-axis')
    plt.show()
if __name__ == "__main__":
    plot_3d_surface()