• UnRelatedBurner@sh.itjust.works
        link
        fedilink
        English
        arrow-up
        28
        arrow-down
        1
        ·
        2 months ago

        Uhm, 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
          link
          fedilink
          English
          arrow-up
          22
          ·
          edit-2
          2 months ago

          x^2 = 9

          <=>

          |x| = sqrt(9)

          would be correct. That way you get both 3 and -3 for x.

          That’s the way your math teacher would do it. So the correct version of the statement in the picture is: “if x^2 = 9 then abs(x) = 3”