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teachings (mander.xyz)
submitted 5 months ago by [email protected] to c/[email protected]
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[-] [email protected] 25 points 5 months ago* (last edited 5 months ago)

You're correct. The square root operator only returns the principal root (the positive one).

So if x^2 = 9 then x = ±√9 = ±3

That's why in something like the quadratic formula we all had to memorize in school its got a "plus or minus" in it: -b ± √...(etc)

[-] [email protected] 9 points 5 months ago

Thanks, I haven't connected the dots to that (+-) sign and this problem.

[-] [email protected] 1 points 5 months ago

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...

[-] [email protected] 5 points 5 months ago

I think your calculator is interpreting that as -(3^2) and not (-3)^2

[-] [email protected] 3 points 5 months ago

Oh derp. Yep it is.

Was better when calcs had a +/- button.

And I remembered the math rule too.

[-] [email protected] 1 points 5 months ago

GD I am just realizing how long its been since I did math in my head without a programming language..

I should take a math class again or something and refresh that knowledge.

this post was submitted on 17 Apr 2024
763 points (98.1% liked)

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