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

fig = plt.figure()
#ax = Axes3D(fig)

#X = np.arange(-20, 20, 0.5)
#xlen = len(X)
#Y = np.arange(-20, 20, 0.5)
#ylen = len(Y)
#X, Y = np.meshgrid(X, Y)

#fig = plt.figure()
#for i in [-0.3]:
#   j = i*i
#    Z = 2*X*Y*i*(4-j) + (X*X+Y*Y)*j*(6-2*j)
#    surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1,
#        linewidth=0, antialiased=True)

#ax = fig.add_subplot(1,1,1)
#x = np.arange(-1,5,0.1)
#y = (((4*x -24)*x +36)*x-16)*x 
#z = 0*x
#ax.plot(x,y,x,z,antialiased=True)

ax = fig.add_subplot(1,1,1)
x = np.arange(0,1,0.01)
y = np.sqrt((x-1)*(x+2)/((x+1)*(x-2)))
ax.plot(x,y)

plt.show()