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Mathematics 8 Online
OpenStudy (anonymous):

need help on the attachment

OpenStudy (anonymous):

is it the same one

OpenStudy (anonymous):

well if you could go back to the old post because I wasn't getting negative for 3

OpenStudy (anonymous):

alright so i found out why it was becoming positive when it should be negative... the derivative of that function is \[\frac{-x^2+2x+8}{(x^2+8)^2}\]

OpenStudy (anonymous):

yeah

OpenStudy (anonymous):

so to get rid of the negative multiply by 1 (-1/-1) \[\frac{x^2-2x-8}{-(x^2+8)^2}\]

OpenStudy (anonymous):

wait you could do that

OpenStudy (anonymous):

i'm not changing the equations by multiplying by one and -1/-1 is still 1

OpenStudy (anonymous):

so instead of the bottom always being positive it will be negative

OpenStudy (anonymous):

so evreything switches if you get a positive on the top it's negative if you get negative you get positive

OpenStudy (anonymous):

so is -2 also relative maximum

OpenStudy (anonymous):

well actually its probably relative minimum

OpenStudy (anonymous):

-2 if you put it in (x-4)(x+2) test -3 you get (-7)(-1)=positive however the denominator is negative making it negative test -1 you get (-5)(1)=-5 but the negative in the bottom cancels getting positive since it was negative on the left side the function is decreasing and after it's increasing -2 is a minimum

OpenStudy (anonymous):

and yes you can multiply your equation by 1 at any time if you wish .. it sometimes can make something that was super ugly looking turn into something nicer looking (forms of 1 can be (x/x),(2/2)(1/1)(-1/-1)etc.

OpenStudy (anonymous):

how come if I plug -3 into the original numerator which x^2-2x-8 I get a negative

OpenStudy (anonymous):

then the bottom is negative which makes it positive

OpenStudy (anonymous):

actually ignore that I did get a negative for the original numerator

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