3D Contour Plotting in Python using Matplotlib

from mpl_toolkits import mplot3d
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import cm
import math
x = [i for i in range(0, 200, 100)]
y = [i for i in range(0, 200, 100)]
X, Y = np.meshgrid(x, y)
Z = []
for i in x:
    t = []
    for j in y:
        t.append(math.cos(math.sqrt(i*2+j*2)))
    Z.append(t)
fig = plt.figure()
ax = plt.axes(projection='3d')
ax.contour3D(X, Y, Z, 50, cmap=cm.cool)
ax.set_xlabel('a')
ax.set_ylabel('b')
ax.set_zlabel('c')
ax.set_title('3D contour for cosine')
plt.show()

from mpl_toolkits import mplot3d
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import cm
import math
x = [i for i in range(0, 200, 100)]
y = [i for i in range(0, 200, 100)]
X, Y = np.meshgrid(x, y)
Z = []
for i in x:
    t = []
    for j in y:
        t.append(math.tan(math.sqrt(i*2+j*2)))
    Z.append(t)
fig = plt.figure()
ax = plt.axes(projection='3d')
ax.contour3D(X, Y, Z, 50, cmap=cm.cool)
ax.set_xlabel('a')
ax.set_ylabel('b')
ax.set_zlabel('c')
ax.set_title('3D contour for tan')
plt.show()