import numpy as np
x=[2,4,6,1,6,7]
np.diff(x)
np.exp(x)
np.log(x)

a=3
b=5
np.mod(a,b)

import matplotlib.pyplot as plt
plt.ion()

a=4.0+3.5j
plt.plot([0.0,np.real(a)],[0.0,np.imag(a)])
print abs(a)
np.angle(a)

import numpy as np
import matplotlib.pyplot as plt
plt.ion()

a=4.0+3.5j
plt.plot([0.0,np.real(a)],[0.0,np.imag(a)])
print abs(a)
print np.angle(a)
print np.angle(a,deg=0)
print np.angle(a,deg=1)
print np.degrees(np.angle(a))
print np.arctan(np.imag(a)/np.real(a))

x=np.arange(-4,5,0.1)
y=x**4+np.log(2)-np.sqrt(2.5)
plt.plot(x,y,'.',color='green')