Not having heard of something is always understandable, and it's pretty immature to make fun or "feign surprise" when someone doesn't know something you know.
But not searching to see if something had been posted before on a forum is a bit different[0]
But not searching to see if something had been posted before on a forum is a bit different[0]
[0] https://hn.algolia.com/?q=inverse+square+root