The function is .
The function represents exponential decay.
The above function the base is , is between 0 and 1.
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=897a612eb985d0316540f054db7226b9.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=d93f4e0113e9d1b21f5af9aaed21c03b.png\")
, is between 0 and 1.![\"\"](\"/userfiles/image/steps_images/solution.JPG\")