How to Prove a Function is Surjective | Logic and Proofs

To prove a function is surjective we must take an arbitrary element from its codomain and prove its domain has an element which gets mapped to the taken codomain element. We complete three examples of proving a function is a surjection (also called "onto"). #proofs
0:00 Definition of Surjective
0:43 Problem 1
2:33 Problem 2
4:49 Problem 3
8:53 Problem 4
12:36 Recap and Outro
What is a surjective function?: • Surjective Functions (...
Logic and Proofs Course: • Logic and Proofs
Logic and Proofs Exercises:
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[@titan1235813]

Man, I had to stop at 2:38 because I needed to subscribe, and this is the very first video of yours that I've ever seen. Okay, I'll keep watching until the end. 👏🏻👏🏻👏🏻

[@WrathofMath]

Thank you! I'm trying to make the most excellent videos I can on every topic. Let me know if you have any questions!

[@Sarah._.s889]

Please do make a video for bijective🙏

[@punditgi]

Looks like you are really onto something with surjections! 😊

[@WrathofMath]

Certainly - on the map of mathematical topics, this is well inside of my conquered domain, and here I function effectively as power surj-es through me!

[@tjn7682]

@@WrathofMath the math dad jokes 🤣😭

[@muhammadsaif4849]

Write a surjective function f:z×z>R

[@WrathofMath]

This is not possible because ZxZ is a countable set. The Cartesian product of any countable set with itself is also countable, so one will not be able to map it onto the reals.

[@sounbframe3602]

997 views, 😬😬😬😬