How should I treat -x^2?  TOPIC_SOLVED

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How should I treat -x^2?

Postby geramul on Tue Nov 06, 2012 2:00 am

From what I understand there's a difference of opinions when it comes to this. Some people look at it as -(x^2) and others -x^2. Both give different answers which is why I'm asking what should I do when I have something like in front of me?
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Postby stapel_eliz on Tue Nov 06, 2012 2:23 am

geramul wrote:From what I understand there's a difference of opinions when it comes to this. Some people look at it as -(x^2) and others -x^2. Both give different answers which is why I'm asking what should I do when I have something like in front of me?

There is no difference between "-x2" and "-(x2)"; they mean the same thing. :wink:
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Re: How should I treat -x^2?

Postby geramul on Tue Nov 06, 2012 2:50 am

Wouldn't -x2 mean -x * -x which would result in a positive? Compared to -(x2), for the sake of this lets say x is 2. So -(22) = -(4) = -4.
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  TOPIC_SOLVED

Postby stapel_eliz on Tue Nov 06, 2012 1:33 pm

geramul wrote:Wouldn't -x2 mean -x * -x...?

No; "-x2" means "the negative of the square of x", or "-[(x)(x)]". On the other hand, "(-x)*(-x)" means "the square of negative x", or "(-x)2 = (-1)(-1)(x)(x) = (+1)(x2) = x2".

In other words, the minus of the square does NOT equal the square of the minus; -(x2) = -x2, but (-x)2 = +x2. :wink:
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Re: How should I treat -x^2?

Postby geramul on Tue Nov 06, 2012 8:39 pm

Ah ok. Thanks :).
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