Number Theory | Quadratic Reciprocity Examples

We determine if certain numbers are quadratic residues using the Legendre symbol and its properties, including quadratic reciprocity.

[georgesadler]

Professor Penn, thank you for all the examples that defines the Quadratic Reciprocity Theorem.

[zeromangahunter]

Wonderful. I'm going to send my students a link to this video. =)

[teddysmith]

I don’t know why but this video got recommended to me even though I have no understanding of what’s happening. As a result, I am so confused. But it sounds like you’re right so I guess I’ll just go rethink my entire understanding of math.

[astrophilip]

can you flip like that when one of the numbers is composite (like in the example at 5:29 )?

[treeofknowledge]

Thanks a lot for wonderful explanation.

[egberthuizinga]

195 square at the end, where coms that from?

[matanmalka]

can you flip 57/523? cause 57 is not prime...shouldnt you factor it to 19/523 and 3/523 and solve from there?

[余淼-eb]

7:56 how to obtain the square root solutions \pm 195?

[nbpereda]

Thanks for this video. Very helpful. One question though. Is it okay to not flip at 1:34 since 5 and 31 are both primes and it's quite easy to know what they are congruent to mod 4?