import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
import math

a=3
b=5

get_ipython().magic('matplotlib notebook')
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')

x=np.linspace(-3.0,3.0,num=500)
y=((b2)*(1-(x2)/(a2))).5

ax.plot(x,y)
ax.plot(x,-y)