Calculating pi using machin-like formula

Author: Karan Goel

Numbers/pi.py

@@ -1,7 +1,10 @@
 # Find PI to the Nth Digit
 
-import math
+from math import *
 
 digits = raw_input('Enter number of digits to round PI to: ')
 
-print ('{0:.%df}' % min(20, int(digits))).format(math.pi) # nested string formatting
+# print ('{0:.%df}' % min(20, int(digits))).format(math.pi) # nested string formatting
+
+# calculate pi using Machin-like Formula
+print ('{0:.%df}' % min(30, int(digits))).format(4 * (4 * atan(1.0/5.0) - atan(1.0/239.0)))