diff --git a/Book3_Ch17_Python_Codes/Bk3_Ch17_01.py b/Book3_Ch17_Python_Codes/Bk3_Ch17_01.py
index 79f863e..44801f8 100644
--- a/Book3_Ch17_Python_Codes/Bk3_Ch17_01.py
+++ b/Book3_Ch17_Python_Codes/Bk3_Ch17_01.py
@@ -118,3 +118,5 @@
 
 ax.set_xlim(-3,3)
 ax.set_ylim(-1.25,1.25)
+
+plt.show()
\ No newline at end of file
diff --git a/Book3_Ch17_Python_Codes/Bk3_Ch17_02.py b/Book3_Ch17_Python_Codes/Bk3_Ch17_02.py
index df51c83..8bc08fa 100644
--- a/Book3_Ch17_Python_Codes/Bk3_Ch17_02.py
+++ b/Book3_Ch17_Python_Codes/Bk3_Ch17_02.py
@@ -124,3 +124,5 @@
 ax.set_ylim(np.floor(error.min()),np.ceil(error.max()))
 ax.spines['right'].set_visible(False)
 ax.spines['top'].set_visible(False)
+
+plt.show()
\ No newline at end of file
diff --git a/Book3_Ch18_Python_Codes/Bk3_Ch18_01.py b/Book3_Ch18_Python_Codes/Bk3_Ch18_01.py
index 14c0eb6..20bada9 100644
--- a/Book3_Ch18_Python_Codes/Bk3_Ch18_01.py
+++ b/Book3_Ch18_Python_Codes/Bk3_Ch18_01.py
@@ -58,3 +58,5 @@
 integral_a_b_v2 = float(integral_a_b_v2)
 
 ax.set_title(r'$\int_a^b  f(x) = %0.4f$'%integral_a_b)
+
+plt.show()
diff --git a/Book3_Ch18_Python_Codes/Bk3_Ch18_02.py b/Book3_Ch18_Python_Codes/Bk3_Ch18_02.py
index c83f207..6171ae3 100644
--- a/Book3_Ch18_Python_Codes/Bk3_Ch18_02.py
+++ b/Book3_Ch18_Python_Codes/Bk3_Ch18_02.py
@@ -90,3 +90,5 @@
 ax.set_xlabel('x')
 ax.set_ylabel('Integral, F(x)')
 ax.grid(linestyle='--', linewidth=0.25, color=[0.75,0.75,0.75])
+
+plt.show()
\ No newline at end of file
diff --git a/Book3_Ch18_Python_Codes/Bk3_Ch18_03.py b/Book3_Ch18_Python_Codes/Bk3_Ch18_03.py
index c9bdcf3..9bffb37 100644
--- a/Book3_Ch18_Python_Codes/Bk3_Ch18_03.py
+++ b/Book3_Ch18_Python_Codes/Bk3_Ch18_03.py
@@ -10,6 +10,10 @@
 
 from sympy import oo, erf, lambdify
 import numpy as np
+from matplotlib import pyplot as plt 
+from sympy import *
+
+x = Symbol('x')
 
 x_array = np.linspace(-3,3,100)
 
@@ -30,3 +34,5 @@
 ax.set_xlabel('x')
 ax.set_ylabel('erf(x)')
 ax.grid(linestyle='--', linewidth=0.25, color=[0.75,0.75,0.75])
+
+plt.show()
diff --git a/Book3_Ch18_Python_Codes/Bk3_Ch18_06.py b/Book3_Ch18_Python_Codes/Bk3_Ch18_06.py
index 3efb925..ca48a15 100644
--- a/Book3_Ch18_Python_Codes/Bk3_Ch18_06.py
+++ b/Book3_Ch18_Python_Codes/Bk3_Ch18_06.py
@@ -10,6 +10,7 @@
 
 import numpy as np
 from scipy.special import factorial
+from matplotlib import pyplot as plt 
 
 n_array = np.linspace(0,10,11)
 
@@ -25,3 +26,5 @@
 plt.tight_layout()
 plt.xlabel('n')
 plt.ylabel('Estimate of $\pi$')
+
+plt.show()
diff --git a/Book3_Ch18_Python_Codes/Bk3_Ch18_07.py b/Book3_Ch18_Python_Codes/Bk3_Ch18_07.py
index 5f35c16..dc10081 100644
--- a/Book3_Ch18_Python_Codes/Bk3_Ch18_07.py
+++ b/Book3_Ch18_Python_Codes/Bk3_Ch18_07.py
@@ -6,7 +6,7 @@
 # Beijing, China, 2022
 ###############
 
-Bk3_Ch18_07.py
+# Bk3_Ch18_07.py
 
 import numpy as np
 import matplotlib.pyplot as plt
@@ -143,3 +143,5 @@
 plt.gca().spines['top'].set_visible(False)
 plt.xlabel('x')
 plt.ylabel('f(x)')
+
+plt.show()
diff --git a/Book3_Ch18_Python_Codes/Bk3_Ch18_08.py b/Book3_Ch18_Python_Codes/Bk3_Ch18_08.py
index e235fd9..644c3fc 100644
--- a/Book3_Ch18_Python_Codes/Bk3_Ch18_08.py
+++ b/Book3_Ch18_Python_Codes/Bk3_Ch18_08.py
@@ -6,7 +6,7 @@
 # Beijing, China, 2022
 ###############
 
-Bk3_Ch18_08.py
+# Bk3_Ch18_08.py
 
 from mpl_toolkits.mplot3d import axes3d
 import matplotlib.pyplot as plt