Was plagiarizing a math proof unethical?

[Jamin2112]

Suppose there's a difficult proof on one of my homework problems in an undergrad course, and suppose I find on the internet a clever, elegant proof whose basic framework I use to construct a slightly modified proof, perhaps with some added explanation (for example, add a "because" or "since" where formerly the reader was supposed to make the inference) to show that I fully understand what I am writing down. Is this unethical on my part? Should I cower away in shame?

 

[mathwonk]

just give credit to the source. and then try to think of your own proof as well.

be careful, this can be embarrassing if you do not give credit and even if you do.

I once had a student "correct" my solution to a problem because they found a different answer to it online. Unfortunately for them i was right and the internet was wrong.originally they gave the solution without attribution, i corrected the problem, and they argued with me. when i asked why they disagreed they said well it said otherwise on the internet. this did not impress me favorably.