lib/muflax/math.rb in muflax-0.3.13 vs lib/muflax/math.rb in muflax-0.3.14

@@ -25,7 +25,15 @@
       n = 1
       n += 1 while θ(n) < exceptions
       n
     end
     alias :sufficient :sufficiency
+
+    def factorial n
+      (2..n).reduce(1){|f, x| f * x}
+    end
+
+    def choose k, n
+      Math.factorial(n) / (Math.factorial(k) * Math.factorial(n - k))
+    end
   end
 end