The Value of ABS[?]Date: 08/24/2010 at 22:18:19 From: Jen Subject: When you use absolute value in finding roots? In class sometimes when the teacher is at the board doing problems with roots and lots of variables, all of a sudden an absolute value symbol will appear in the answer. When exactly does this pair of vertical lines come into play? Date: 08/25/2010 at 10:11:27 From: Doctor Ian Subject: Re: When you use absolute value in finding roots? Hi Jen, Suppose I know that the value of some variable, if squared, is equal to 4: x^2 = 4 There are TWO solutions to this equation -- one positive, and one negative: x^2 = 4 x = 2 or -2 The absolute value symbol is a way of specifying both of those values at once: x^2 = 4 x = 2 or -2 |x| = 2 This means the same thing as the previous line. It's just a convenience, so you don't have to keep writing subsequent equations twice (once for the positive value, and again for the negative value). Does it make more sense now? - Doctor Ian, The Math Forum http://mathforum.org/dr.math/ |
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