• rasensprenger@feddit.de
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      10 months ago

      The square root of x is usually defined as the positive real number that squares to x, so x^2 = 4 => x = ±2 but sqrt(4) = 2, not ±2

      The complex sqrt function is multivalued, but that opens a whole other can of worms

      • digdug@kbin.social
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        10 months ago

        And even if you allowed sqrt(4) = ±2, it would still be invalid to evaluate it to -2 on one side of the equation, but then use +2 on the other side.