{"id":2384,"date":"2020-11-18T09:55:12","date_gmt":"2020-11-18T04:25:12","guid":{"rendered":"http:\/\/physicscatalyst.com\/article\/?p=2384"},"modified":"2022-11-04T12:06:28","modified_gmt":"2022-11-04T06:36:28","slug":"vertical-line-test-for-functions-and-relation","status":"publish","type":"post","link":"https:\/\/physicscatalyst.com\/article\/vertical-line-test-for-functions-and-relation\/","title":{"rendered":"Vertical line test for functions and relation"},"content":{"rendered":"\n<p>In this post,we will be checking the vertical line test and how is it used. Examples and Problems are also given to help the student. This will also answer the question How do you know if the graph is a function?<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What is Vertical line test<\/h2>\n\n\n\n<p>A <a href=\"https:\/\/physicscatalyst.com\/maths\/relation-in-maths.php\"  rel=\"noopener noreferrer\">relation (in math)<\/a> is a <a href=\"https:\/\/physicscatalyst.com\/maths\/functions-in-maths.php\"  rel=\"noopener noreferrer\">function<\/a> in math if no pair of the relation has the same first elements. On the graph, two points will lie in the same vertical line if and only if the first coordinate of the two points is the same. Therefore if a vertical line intersects the Relation graph at two points then it is not a function. This is called the <strong>Vertical line test<\/strong>. If all vertical lines intersect a curve at most once then the curve represents a function.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to use the it<\/h2>\n\n\n\n<p>To use it, take a rule or other straight edge and draw a line parallel to the y-axis for any chosen value of x. If the vertical line you drew intersects the graph more than once for any value of x then the graph is not the graph of a function. If alternatively, a vertical line intersects the graph no more than once, no matter where the vertical line is placed, then the graph is the graph of a function. For example, a curve which is any straight line other than a vertical line will be the graph of a function<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"819\" height=\"460\" src=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical_line.png\" alt=\"vertical line test for functions and relations\" class=\"wp-image-2385\" srcset=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical_line.png 819w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical_line-300x168.png 300w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical_line-660x371.png 660w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical_line-150x84.png 150w\" sizes=\"auto, (max-width: 819px) 100vw, 819px\" \/><\/figure><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Examples <\/h2>\n\n\n\n<ol class=\"wp-block-list\"><li>Upward Parabola<br>$y=2x^2$<br><a href=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-upward-parabola.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-5006\" src=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-upward-parabola.png\" alt=\"\" width=\"332\" height=\"370\" srcset=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-upward-parabola.png 332w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-upward-parabola-269x300.png 269w\" sizes=\"auto, (max-width: 332px) 100vw, 332px\" \/><\/a><br>Clearly this is a function<\/li><li><a href=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-1.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-5007\" src=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-1.png\" alt=\"\" width=\"342\" height=\"278\" srcset=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-1.png 342w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-1-300x244.png 300w\" sizes=\"auto, (max-width: 342px) 100vw, 342px\" \/><\/a><br>Clearly this is not a function<\/li><li>The relation<br>$y=2x^3$<br><a href=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-2.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-5008\" src=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-2.png\" alt=\"\" width=\"275\" height=\"364\" srcset=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-2.png 275w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-2-227x300.png 227w\" sizes=\"auto, (max-width: 275px) 100vw, 275px\" \/><\/a><br>Clearly this is a function<\/li><li>The relation$ \\frac {x^2}{a^2} + \\frac {y^2}{b^2} =1$<br><a href=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-3.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-5009\" src=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-3.png\" alt=\"\" width=\"291\" height=\"333\" srcset=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-3.png 291w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-3-262x300.png 262w\" sizes=\"auto, (max-width: 291px) 100vw, 291px\" \/><\/a><br>Clearly this is not a function<\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Practice Problems for Vertical Line test<\/h2>\n\n\n\n<ol class=\"wp-block-list\"><li>Find out if the graph represent functions using Vertical Line check<a href=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-1.png\"><img loading=\"lazy\" decoding=\"async\" width=\"741\" height=\"388\" class=\"alignnone size-full wp-image-5010\" src=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-1.png\" alt=\"\" srcset=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-1.png 741w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-1-300x157.png 300w\" sizes=\"auto, (max-width: 741px) 100vw, 741px\" \/><\/a><\/li><li>Find out if the below graph are for function using vertical line test<a href=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-2.png\"><img loading=\"lazy\" decoding=\"async\" width=\"827\" height=\"464\" class=\"alignnone size-full wp-image-5011\" src=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-2.png\" alt=\"\" srcset=\"https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-2.png 827w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-2-300x168.png 300w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-2-768x431.png 768w, https:\/\/physicscatalyst.com\/article\/wp-content\/uploads\/2014\/09\/vertical-line-test-worksheet-2-800x449.png 800w\" sizes=\"auto, (max-width: 827px) 100vw, 827px\" \/><\/a><\/li><\/ol>\n\n\n\n<p><strong>Related Articles<\/strong><br><a href=\"https:\/\/en.wikipedia.org\/wiki\/Vertical_line_test\">https:\/\/en.wikipedia.org\/wiki\/Vertical_line_test<\/a><br><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A relation is a function if no pair of the relation has the same first elements. On the graph,two points will lie in the same vertical line if and only if the first coordinate of the two points are same. Therefore if a vertical line intesect the Relation graph at two points then it is not a function. This is called the Vertical line test. If all vertical lines intersect a curve at most once then the curve represents a function<\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[498],"tags":[],"class_list":["post-2384","post","type-post","status-publish","format-standard","hentry","category-maths"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - 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On the graph,two points will lie in the same vertical line if and only if the first coordinate of the two points are same. Therefore if a vertical line intesect the Relation graph at two points then it is&hellip;","_links":{"self":[{"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/posts\/2384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/comments?post=2384"}],"version-history":[{"count":2,"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/posts\/2384\/revisions"}],"predecessor-version":[{"id":6792,"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/posts\/2384\/revisions\/6792"}],"wp:attachment":[{"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/media?parent=2384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/categories?post=2384"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/physicscatalyst.com\/article\/wp-json\/wp\/v2\/tags?post=2384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}