title: In this python code, the result plot is not being shown
body: <p>This is my python code and I don't know how to make it work correctly!
  I want to plot 2 graph in 2 rows by subplot.
  This is what it says:   ----------&gt;
  Exception has occurred: AttributeError
  'AxesSubplot' object has no attribute 'show'
  File &quot;E:# Civil Engineering Undergraduate\Projects\Python\NUMPY_1\import numpy as np.py&quot;, line 28, in 
  pp1.show()</p>
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  kesai=0.0
  k=2*541*3*29000/(16*12)**3+597*3*29000/(20*12)**3
  w=30
  m=w/386.4
  Wn=(k/m)**0.5
  Wd=Wn*(1-kesai**2)**0.5
  pi=3.141592654
  Tp=2
  P0=20
  n=5
  nn=1000
  Omeg=2*pi/Tp
  t=np.linspace(0,10,nn)
  dt=t[1]-t[0]
  Pt=P0*np.cos(t*Omeg)/np.abs(np.cos(t*Omeg))
  pp1=plt.subplot(2,1,1)
  pp1.plot(t,Pt,'r')
  f=0
  for i in range(1,n+1):
      an=(2*P0)/(i*Omeg*Tp)*(np.sin(i*Omeg*(Tp/4))-np.sin(i*Omeg*(3*Tp/4))+\
                             np.sin(i*Omeg*(Tp/4))+np.sin(i*Omeg*(Tp))-np.sin(i*Omeg*(3*Tp/4)))
      print('Pt=',an,'cos(',i,'*',Omeg,'*t)')
      f=f+an*np.cos(i*Omeg*t)
  pp1.plot(t,f,'k')
  pp1.title:'External Load'
  #pp1.show()
  c1=Pt*np.exp(kesai*Wn*t)*np.cos(Wd*t)
  c1=0.5*dt*(c1[0:nn-1]+c1[1:nn])
  A=np.exp(-kesai*Wn*t)*np.sin(Wd*t)
  c2=Pt*np.exp(kesai*Wn*t)*np.sin(Wd*t)
  c2=0.5*dt*(c2[0:nn-1]+c2[1:nn])
  B=np.exp(-kesai*Wn*t)*np.cos(Wd*t)
  U=c1*A[0:nn-1]+c2*B[0:nn-1]
  pp2=plt.subplot(2,1,2)
  pp2.plot(t[0:nn-1],U)
  pp2.title:'Response'
  #pp2.show()
  </code></pre>
  <p>Thanks for helps</p>