Update numpy_questions.py

Author: Ahmed-Semah

numpy_questions.py

@@ -46,7 +46,7 @@ def max_index(X):
         raise ValueError("Input is not a 2D array")
     i, j = np.unravel_index(np.argmax(X), X.shape)
     return i, j
-    
+
 
 
 def wallis_product(n_terms):
@@ -68,4 +68,13 @@ def wallis_product(n_terms):
     """
     # XXX : The n_terms is an int that corresponds to the number of
     # terms in the product. For example 10000.
-    return 0.
+
+    if n_terms < 0:
+        raise ValueError("n_terms should be a positive integer")
+    if n_terms == 0:
+        return 1.
+
+    pi = 1.
+    for i in range(1, n_terms+1):
+        pi *= 4*i**2/(4*i**2-1)
+    return 2*pi