diff --git a/.gitignore b/.gitignore
new file mode 100644
index 00000000000..b9b615a3300
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,8 @@
+# History files
+.Rhistory
+
+# Example code in package build process
+*-Ex.R
+
+# R data files from past sessions
+.Rdata
\ No newline at end of file
diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..ad7e272b675 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,62 @@
-## Put comments here that give an overall description of what your
-## functions do
+## makeCacheMatrix - creates a "special" matrix which can cache its
+## inverse. Remark: matrix supplied needs to be invertible.
+##
+## cacheSolve - computes the inverse of the special matrix generated with
+## makeCacheMatrix. If the cache has already been calculated and the special matrix
+## has not been changes, the cacheSolve retrieves the cached inverse value.
 
-## Write a short comment describing this function
+## Function makeCacheMatrix contains a function to
+## 1. set the value of the matrix
+## 2. get the value of the matrix
+## 3. set the value of the inverse
+## 4. get the value of the inverse
+## 5. assemble a list of all the functions defined above
 
 makeCacheMatrix <- function(x = matrix()) {
-
+        #set the inverse value to NULL
+        inv <- NULL
+        # 1. set the value of the matrix
+        set <- function(y) {
+                x <<- y
+                # set inv back to NULL because the matrix changed
+                inv <<- NULL
+        }
+        # 2. get the value of the matrix
+        get <- function() x
+        # 3. set the inverse
+        setinv <- function(inverse) inv <<- inverse
+        # 4. get the inverse
+        getinv <- function() inv
+        
+        # 5. assemble a list of all the functions defined above
+        list(set = set, get = get,
+             setinv = setinv,
+             getinv = getinv)
 }
 
 
-## Write a short comment describing this function
+## cacheSolve - calculates the inverse of the special
+## matrix supplied from the makeCacheMatrix function.
+## 1. check if the inverse has already been calculated.
+## If true, get the inverse from the cache and skip the
+## calculation. 
+## 2. If false, 3. calculates the inverse of the
+## matrix and 4. sets the value of the inverse in the cache with
+## the setinv function. 5. returns the newly calculated value.
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
-}
+        # 1. check if the inverse is calculated and cached
+        inv <- x$getinv()
+        if(!is.null(inv)) {
+                message("getting cached data")
+                return(inv)
+        }
+        # 2. not cached, place the matrix into data
+        data <- x$get()
+        # 3. calculate the inverse
+        inv <- solve(data, ...)
+        # 4. afterwards, cache the inverse
+        x$setinv(inv)
+        # 5. finally, return the newly calculated inverse
+        inv
+}
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