diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..7db67600ed3 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,36 @@
-## Put comments here that give an overall description of what your
-## functions do
+## makeCachematrix creates a special list of functions
+## that calculate inverse of a matrix and caches it
 
-## 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
+  }
+  get <- function() x
+  setinv <- function(solve) I <<- solve
+  getinv <- function () I
+  list (set = set, get = get,
+        setinv = setinv,
+        getinv = getinv)
 }
 
 
-## Write a short comment describing this function
+## This function computes the inverse of the special "matrix" 
+##returned by makeCacheMatrix above.
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+## Return a matrix that is the inverse of 'x'
+  I <-x$getinv()
+  if(!is.null(I)) {
+    message("getting cached data")
+    return(I)
+  }
+  data <-x$get()
+  I <-solve(data,...)
+  x$setinv(I)
+  I
 }