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mathcalculus
Group Title
mathcalculus
HELP: Determine the values of where the tangent line is horizontal for the function:
 11 months ago
 11 months ago
mathcalculus Group Title
mathcalculus HELP: Determine the values of where the tangent line is horizontal for the function:
 11 months ago
 11 months ago

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mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
i know i have to find the derivative and set it to zero but it's not coming out to be correct. can anyone help me
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
so i did 3x^26x4=0
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
i tried to use the quadratic formula and got sqrt(21)+3/3
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
+ or  sqrt(21)+3/3
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
also aka 2.52753...
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
derivative seems correct
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
to find what x = to... ?
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
i used quadratic formula
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@dumbcow dont i have to do that to find x??
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
im getting it wrong,
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
yes everything looks correct to me...do they want exact or decimal answer?
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
http://www.wolframalpha.com/input/?i=3x%5E26x4%3D0
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
can i use quadratic formula for ths one?
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@dumbcow
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
????????????????????????
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
yes of course you use quadratic formula...thats how you got your answer that i said looked correct
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
im not getting that using quadratic formula
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
im getting something totally different and wrong
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
\[x = \frac{3 \pm \sqrt{21}}{3}\]
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
yes! but from 6+2*sqrt(21)/6?
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
shouldnt it be 1+ or  sqrt 21/3
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
same thing, just a matter of splitting up fraction or keeping it as single fraction
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
no it's not because the answer is 1+ sqrt (7/3) gives me 2.52753 and 1+sqrt 21/3 gives me 1.86086!
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@dumbcow
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
hmm \[\frac{\sqrt{7}}{\sqrt{3}} = \frac{\sqrt{21}}{3} \]
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
hmmm?
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@dumbcow
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
try it on a calculator.
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
http://www.wolframalpha.com/input/?i=1%2Bsqrt%287%2F3%29+%2C+1%2Bsqrt%2821%29%2F3
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
oh you added the "1" before dividing by "3"
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
okay from my answer.... not the internet.. 6+2 sort(21)/3.... where do i go from there?
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
well it should be a 6 on bottom
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
no i didn't add anything.
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
okay sure a 6. i thought it could be a 3 to narrow it down
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
so 6+or2sqrt(21)/6
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
i dont see the problem, you posted answer in beginning... " i tried to use the quadratic formula and got sqrt(21)+3/3 "
 11 months ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
so it is a 3 in the denominator!
 11 months ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.1
\[\frac{6 \pm 2\sqrt{21}}{6} = \frac{2(3 \pm \sqrt{21})}{6} = \frac{3 \pm \sqrt{21}}{3}\]
 11 months ago
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