added some comments

Author: Erik Larson

cachematrix.R

@@ -1,10 +1,14 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Matrix inversion is usually a costly computation and their may be some 
+## benefit to caching the inverse of a matrix rather than compute it 
+## repeatedly. This assignment is to write a pair of functions that cache
+## the inverse of a matrix.
 
-## Write a short comment describing this function
+## This function creates a special "matrix" object that can cache its inverse.
 
 makeCacheMatrix <- function(x = matrix()) {
+	
 	i <- NULL
+	
     set <- function(y) {
             x <<- y
             i <<- NULL
@@ -18,7 +22,10 @@ makeCacheMatrix <- function(x = matrix()) {
 }
 
 
-## Write a short comment describing this function
+## This function computes the inverse of the special "matrix" returned by 
+## makeCacheMatrix above. If the inverse has already been calculated (and the 
+## matrix has not changed), then the cachesolve should retrieve the inverse
+## from the cache.
 
 cacheSolve <- function(x, ...) {
         ## Return a matrix that is the inverse of 'x'