Mathematics
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OpenStudy (anonymous):
[2(-2+h)^{2} +3(-2+h)] -2= ?
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OpenStudy (anonymous):
\[[2(-2+h)^{2} +3(-2+h)] -2= ?\]
thanks
OpenStudy (paxpolaris):
Do you want to factor:\[2(-2+h)^{2} +3(-2+h) -2\]
Assume -2+h=x
OpenStudy (anonymous):
no don't factor, it's only a
part of a problem
OpenStudy (anonymous):
just simplify
OpenStudy (anonymous):
fyi, it's the whole bracket minus 2
[2(-2+h)^{2} +3(-2+h)] -2= ?
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OpenStudy (paxpolaris):
brackets don't matter ...it's still the same
OpenStudy (anonymous):
oh hehe
:)
OpenStudy (paxpolaris):
So just the expanded form is your answer
OpenStudy (paxpolaris):
??
OpenStudy (anonymous):
so what does it come to? my online hw has it coming to -5h+5h^2
how do they get that?
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OpenStudy (anonymous):
when i do it, it comes to 3h+2h^2
OpenStudy (paxpolaris):
\[2\left( h^2-4h+4 \right)+(3h-6)-2\]
OpenStudy (paxpolaris):
it can't be 5h^2
OpenStudy (paxpolaris):
or something is wrong with the question you typed above
OpenStudy (anonymous):
my mistake was distributing the square
do you want to see the whole problem?
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OpenStudy (paxpolaris):
sure
OpenStudy (anonymous):
so
f'(a)=lim [f(a+h)-f(a)]/h
h-->0
OpenStudy (anonymous):
\[f(x)=2x ^{2}+3x\]
a=-2
OpenStudy (anonymous):
\[f'(-2)=\lim h-->0 [(2(-2+h)^{2}+3(-2+h))-2]/h\]
OpenStudy (paxpolaris):
\[\Large f'(a)=\lim_{h \rightarrow 0}{f(a+h)-f(a) \over h}\]... that the definition of the derivative...ok
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OpenStudy (anonymous):
yes exactly!
OpenStudy (anonymous):
\[f'(-2)=\lim_{h \rightarrow 0} (2(-2+h)^{?} +3(-2+h))-2\div h\]
OpenStudy (anonymous):
then after that is the answer
\[\lim_{h \rightarrow 0} -5h+2h ^{2}\div h\]
OpenStudy (paxpolaris):
that's right
OpenStudy (anonymous):
but how do they get there?
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OpenStudy (paxpolaris):
back to your original question:
\[2(−2+h)^2+3(−2+h)−2\]\[=(2h^2-8h+8)+(3h-6)-2\]\[=2h^2+(-8h+3h)+(8-6-2)\]
OpenStudy (anonymous):
oh my god
yeah i was doing the square wrong
OpenStudy (anonymous):
you are a gentleman, thanks
so easy, i'm just not thinking thank you so much
OpenStudy (paxpolaris):
\[so,\ \Large f'(-2)=-5\]