![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
(a)
\One-to-one function definition:
\A function is called a one-to-one function if it never takes on the same value twice.
\![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4e727956a79b5a55d49adc6b30ddb519.png\")
whenever ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b18eff241a1af630f98f9789321dc146.png\")
.
![\"\"](\"/userfiles/image/steps_images/step2.JPG\")
(b)
\Horizontal line test is used to determine one to one function.
\Horizontal line test:
\A function is one-to-one if and only if no horizontal line intersects its graph more than once.
\It means that any horizontal line in the graph must cross the curve at one point only.
\![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
(a) A function is called a one-to-one function if it never takes on the same value twice.
\(b) horizontal line test is used to determine one to one function.