Is this biconditional true?-A number is greater than 3 if an only if its square is greater than 9?

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2007-05-13 14:00:36 · 4 answers · asked by Anna B 1 in Science & Mathematics ➔ Mathematics

Nope this is wrong because if -4 were squared, it would be 16, which is larger than 9. -4 is also less than 3.

2007-05-13 14:03:52 · answer #1 · answered by UnknownD 6 · 0⤊ 0⤋

The magnitude of the number is greater than 3 if it's square is greater than 9.

-5 < 3
but
(-5)^2 > 9

2007-05-13 21:07:43 · answer #2 · answered by Dr D 7 · 0⤊ 0⤋

No, the counterexample is (-4)Â² > 9, but -4 is not greater than 3.

2007-05-13 21:09:11 · answer #3 · answered by Kathleen K 7 · 0⤊ 0⤋

It isn't true at all. A number can be less than -3, and the same would hold.

2007-05-13 21:04:59 · answer #4 · answered by cattbarf 7 · 0⤊ 0⤋