Vertical Line Test Results
An S-shaped curve awaits its 'test results' from a doctor, who has bad news: it fails the vertical line test and isn't a function.
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Free for classrooms, worksheets, slides and other non-commercial use under CC BY-NC 4.0, with credit to Ben Orlin.
Cartoon by Ben Orlin, Math with Bad Drawings. https://cartoons.mathwithbaddrawings.com/2019-06-12-vertical-line-test-results/ (CC BY-NC 4.0)Transcript
An S-shaped curve: "Do you have the test results, doctor?" Doctor (a wavy function wearing a stethoscope): "Yes, I do. You may want to sit down for this."