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0 pointsmunchler2mo ago0 comments

If sqrt -1 = 0, then (by squaring both sides) -1 = 0, which is clearly unsound.

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Right but there isn't a theorem saying `(sqrt x)^2 = x`, there's a theorem saying `x >= 0 -> (sqrt x)^2 = x`

munchlerOP2mo ago

Ah, that makes sense. Thank you. As long as every use of sqrt has such a condition.

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0 pointsmunchler2mo ago0 comments

If sqrt -1 = 0, then (by squaring both sides) -1 = 0, which is clearly unsound.

Right but there isn't a theorem saying `(sqrt x)^2 = x`, there's a theorem saying `x >= 0 -> (sqrt x)^2 = x`

munchlerOP2mo ago

Ah, that makes sense. Thank you. As long as every use of sqrt has such a condition.

j / k navigate · click thread line to collapse