# is the negative sign part of x?

• Nov 20th 2009, 08:22 PM
REWIND10
is the negative sign part of x?
I have the function (this is exactly how it's written in the paper):

f(x)= -x^2/(x^2-9)

I need to know where exactly the negative is in the numerator:

-(x^2)

OR

(-x)^2

Which is right?

Any help is appreciated! (Happy)
• Nov 20th 2009, 09:07 PM
mr fantastic
Quote:

Originally Posted by REWIND10
I have the function (this is exactly how it's written in the paper):

f(x)= -x^2/(x^2-9)

I need to know where exactly the negative is in the numerator:

-(x^2) Mr F says: This one.

OR

(-x)^2

Which is right?

Any help is appreciated! (Happy)

..
• Nov 20th 2009, 09:08 PM
Unenlightened
$-\left(x\right)^{2} = -(x)(x)$
$\left(-x\right)^{2} = (-x)(-x)= xx$
• Nov 21st 2009, 05:16 AM
mosta86
it is easy , the function is written : f(x)= -x^2/(x^2-9)
so the negative can be for either numerator or denumerator .. as a numerator , it is -X^2 so it gonna be f(x) = (-(x^2))/(x^2-9)
• Nov 21st 2009, 06:25 AM
HallsofIvy
As mosta86 said, it doesn't matter:
$\frac{-x^2}{x^2-9}= \frac{x^2}{-(x^2- 9)}= -\frac{x^2}{x^2- 9}$.

In none of those, however, is this the same as $\frac{(-x)^2}{x^2- 9}= \frac{x^2}{x^2- 9}$.

I suspect that the question should NOT have been "is the negative in the numerator?" (the answer to that is "it doesn't matter") but "is the negative part of what is squared?". The answer to that is NO! For example, $-2^2= -(2)(2)= -4$ NOT $(-2)(-2)= 4$.