Add iterating function and the test for it

testing_project/logistic.py

@@ -1,4 +1,13 @@
 # Your code goes here
+import numpy as np
 
 def f(x, r):
     return r * x * (1 - x)
+
+def iterate_f(x, r, n_iterations):
+    trajectory = np.zeros(n_iterations+1)
+    trajectory[0] = x
+    for i in range(n_iterations):
+        trajectory[i+1] = f(x, r)
+        x = trajectory[i+1]
+    return trajectory