|x| = sqrt(…)
would be correct.
Comment on teachings
UnRelatedBurner@sh.itjust.works 7 months agoUhm, actually 🤓☝️!
Afaik sqrt only returns positive numbers, but if you’re searching for X you should do more logic, as both -3 and 3 squared is 9, but sqrt(9) is just 3.
If I’m wrong please correct me, caz I don’t really know how to properly write this down in a proof, so I might be wrong here. :p
(ps: I fact checked with wolfram, but I still donno how to split the equation formally)
h3ndrik@feddit.de 7 months ago
UnRelatedBurner@sh.itjust.works 7 months ago
Cool! Makes sense to me. Honestly, I’ve never done it this way, but it’s so clean. Love it. Thanks.
criitz@reddthat.com 7 months ago
You’re correct. The square root operator only returns the principal root (basically, the positive one).
So if x ^2^ = 9 then x = ±√9 = ±3
UnRelatedBurner@sh.itjust.works 7 months ago
Thanks, I haven’t connected the dots to that (±) sign and this problem.
Routhinator@startrek.website 7 months ago
Image
Image
So I checked this on my smartphone first, and thought maybe the software is just shit… So then I checked it on a Casio scientific calc, and both agree.
-3^2 = -9… And 9 != -9
… Are all the calculators somehow wrong? What’s the math rule I’m forgetting here…
criitz@reddthat.com 7 months ago
I think your calculator is interpreting that as -(3^2) and not (-3)^2
Routhinator@startrek.website 7 months ago
Image
Oh derp. Yep it is.
Was better when calcs had a +/- button.
And I remembered the math rule too.