SOLUTION: When verifying an identity, why can't you square both sides?

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Question 594645: When verifying an identity, why can't you square both sides?
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Squaring both sides essentially weakens a statement. For example, suppose that



Squaring both sides yields



However the second equation is not equivalent to the first one, as x could equal 1 or -1. You can square both sides when dealing with "if and only if" relations, for example, if you know that x must be positive.