diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..f0d5864c944 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,49 @@
 ## Put comments here that give an overall description of what your
-## functions do
+## functions do:
+## With this two functions we can create a special matrix object that
+## contains the matrix and also its inverse when it has been calculated
+## the first time. This is useful to avoid computing many times the same
+## value with a potentialy time-consuming process.
 
-## Write a short comment describing this function
+## Write a short comment describing this function:
+## "makeCacheMatrix" creates an object that contains information about a 
+## matrix and also its inverse. This object contains 4 functions: "set" 
+## that it's used when creating the object; "get" that allows you to 
+## retrieve the simple matrix; "setinverse" that can store the value of
+## its inverse; and "getinverse" that allows you to retrieve the inverse
+## if it has been calculated (if not it is set to NULL);
 
 makeCacheMatrix <- function(x = matrix()) {
-
+    i <- NULL
+    set <- function(y){
+        x <<- y
+        i <<- NULL
+    }
+    get <- function() x
+    setinverse <- function(solve) i <<- solve
+    getinverse <- function() i
+    list(set = set, get = get,
+         setinverse = setinverse,
+         getinverse = getinverse)
 }
 
 
-## Write a short comment describing this function
+## Write a short comment describing this function:
+## cacheSolve calculates the inverse of an object of those
+## created by makeCacheMatrix. If the inverse of the object
+## has never been calculated yet, it applies solve to the matrix
+## and store the inverse in the object (via "setinverse"). If the 
+## inverse has been obtained before, it retrieves it from the
+## stored value in the object (via "getinverse").
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
-}
+    i <- x$getinverse()
+    if (!is.null(i)){
+    message("getting cached data!")
+    return(i)
+    }
+    data <- x$get()
+    i <- solve(data, ...)
+    x$setinverse(i)
+    i
+}
\ No newline at end of file