diff --git a/numpy_questions.py b/numpy_questions.py
index 07a10c1..4a27638 100644
--- a/numpy_questions.py
+++ b/numpy_questions.py
@@ -18,7 +18,7 @@
 import numpy as np
 
 
-def max_index(X):
+def max_index(X): 
     """Return the index of the maximum in a numpy array.
 
     Parameters
@@ -39,12 +39,20 @@ def max_index(X):
     """
     i = 0
     j = 0
-
     # TODO
+    print(X, np.ndarray)
+    if isinstance(X, np.ndarray):
+        print("")
+    else:
+        raise ValueError("Not an array")
+    if (len(X.shape) != 2):
+        raise ValueError("Not 2D dimension")
 
+    max_indices = np.unravel_index(np.argmax(X), X.shape)
+    i = max_indices[0]
+    j = max_indices[1]
     return i, j
 
-
 def wallis_product(n_terms):
     """Implement the Wallis product to compute an approximation of pi.
 
@@ -64,4 +72,17 @@ 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):
+        return 2.0
+
+    pi = 1.0
+    for i in range(1, n_terms+1):
+        print("boucle", i)
+        left = float((2 * i)/(2 * i - 1))
+        print(left)
+        right = float((2 * i)/(2 * i + 1))
+        print(right)
+        total = left * right
+        pi = pi * total
+        print(pi)
+    return pi*2