1 #!/usr/bin/python

     2 # 5.1

     3 

     4 import scipy as sp

     5 from pylab import *

     6 

     7 n = sp.arange(17)

     8 subplot(2,2,1), stem(n,cos(n*pi/8))

     9 grid,xlabel('n'),ylabel('cos(n*pi/8)')

    10 subplot(2,2,2), stem(n,cos(n*pi/4))

    11 grid,xlabel('n'),ylabel('cos(n*pi/4)')

    12 subplot(2,2,3), stem(n,cos(n*pi/2))

    13 grid,xlabel('n'),ylabel('cos(n*pi/2)')

    14 subplot(2,2,4), stem(n,cos(n*pi))

    15 grid,xlabel('n'),ylabel('cos(n*pi)')

    16 

    17 show()