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

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mathcalculusBest 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
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
so i did 3x^26x4=0
 8 months ago

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

mathcalculusBest ResponseYou've already chosen the best response.0
+ or  sqrt(21)+3/3
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
also aka 2.52753...
 8 months ago

dumbcowBest ResponseYou've already chosen the best response.1
derivative seems correct
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
to find what x = to... ?
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
i used quadratic formula
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
@dumbcow dont i have to do that to find x??
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
im getting it wrong,
 8 months ago

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

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

mathcalculusBest ResponseYou've already chosen the best response.0
can i use quadratic formula for ths one?
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
????????????????????????
 8 months ago

dumbcowBest 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
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
im not getting that using quadratic formula
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
im getting something totally different and wrong
 8 months ago

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

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

mathcalculusBest ResponseYou've already chosen the best response.0
shouldnt it be 1+ or  sqrt 21/3
 8 months ago

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

mathcalculusBest 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!
 8 months ago

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

mathcalculusBest ResponseYou've already chosen the best response.0
try it on a calculator.
 8 months ago

dumbcowBest 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
 8 months ago

dumbcowBest ResponseYou've already chosen the best response.1
oh you added the "1" before dividing by "3"
 8 months ago

mathcalculusBest 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?
 8 months ago

dumbcowBest ResponseYou've already chosen the best response.1
well it should be a 6 on bottom
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
no i didn't add anything.
 8 months ago

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

mathcalculusBest ResponseYou've already chosen the best response.0
so 6+or2sqrt(21)/6
 8 months ago

dumbcowBest 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 "
 8 months ago

mathcalculusBest ResponseYou've already chosen the best response.0
so it is a 3 in the denominator!
 8 months ago

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