![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
Observe the graph: \ \
\The interval are ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=abb6e9e5c7c5a6658cf38178137a1fe1.png\")
,![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b4b8ec3d532890e03a9bbc4267cca607.png\")
and ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=02481552e9644007c97a941661ad9330.png\")
.
Consider the horizontal line ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=a4f8c5730f9412f995989427f42e70fc.png\")
on the graph.
Horizontal line touches the graph atmost once.
The function passes the horizontal test, hence the function is an one-to-one function.
\Therefore the inverse of the function exist.
\\
![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
The inverse of the function exist.