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mathcalculus
Group Title
where is everyone?!? help please! =(
find the extrema: 4x^313x^2+4x+1
max and min:
[1,4]
[0,2]
 one year ago
 one year ago
mathcalculus Group Title
where is everyone?!? help please! =( find the extrema: 4x^313x^2+4x+1 max and min: [1,4] [0,2]
 one year ago
 one year ago

This Question is Closed

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
so i found the derivative: 12x^2 26x +4
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
correct?
 one year ago

heradog Group TitleBest ResponseYou've already chosen the best response.1
I could maybe figure it out for myself on my calculator but I don't know how that would help, are you in webworks?
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
do you know hot to factor: 12x^2 26x +4
 one year ago

heradog Group TitleBest ResponseYou've already chosen the best response.1
I'll try and see if I can help but can't promise so yeah you have the derivative right
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
not on calculator though... i just need to know just in case.
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
i must factor first in order to = to 0
 one year ago

heradog Group TitleBest ResponseYou've already chosen the best response.1
so to find max and min you find the derivative set it = to 0 and solve?
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
yes i have to find the critical points.. then evaluate the point to original function
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
then evaluate with the endpoints. then i'll find max and min
 one year ago

heradog Group TitleBest ResponseYou've already chosen the best response.1
so you have 1/6 and 2 for the critical points right?
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@campbell_st @precal @heradog the more help the better! :( i really need to figure this problem out.
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
well.... i don't know how to factor this exactly: 12x^2 26x +4
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
since derivative is right... then how do i factor it out?
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@dan815
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
dw:1363327156303:dw
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
yes @precal that one is right
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
dw:1363327198254:dw
 one year ago

heradog Group TitleBest ResponseYou've already chosen the best response.1
ok so to factor you pull out the recurring elements I so suck at factoring but lets try it you can multiply every element by 2 giving you 2(6x^213x+2)
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
hm... i did that also... but then i have to find x . critical points.
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
dw:1363327232310:dw
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
dw:1363327276945:dw
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
are you given those intervals? [1,4] and [0,2]
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.0
the stationary points are at (x  2)(12x 2) = 0 so the stationary points are x = 2, x = 1/6 so find the the 2nd derivative and test them for max and min then check you boundary values... an easy way it to graph the curve
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
why not just do a sign analysis with the first d/dx, second d/dx states concave up or concave down doesn't 1st d/dx show max and min
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
kindly, can we stick with these steps.... {Differentiate} {Set f '(x) = 0} {Factor} {solve to get the critical numbers}
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
im already used to them...
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
dw:1363327423329:dw
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@precal what did you do after 2(6x^213x+2) ? i dont understand how you got the x^2....etc after...
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
dw:1363327470127:dw
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
dw:1363327620907:dwit is an old jedi trick called slide and divide, makes factoring easier to do
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.0
the attached image may help
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
max at x=1/6 and min at x=2
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
dw:1363327660835:dw
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
dw:1363327725416:dw
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
what i meant t say how? i know you said a trick way but i don't know how... :/
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.0
the 2nd derivative test is used for determining if the point is a max or min... easier than 1st der and change of sign...
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
true but if this is for a calculus ab class, they are taught to do 1st d/dx to determine max and min
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
stilll dont understand .. :(
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
just factor using whatever technique or strategy you were taught, factoring is a basic skill you will need to for future math courses. I just used a technique I like that helps me factor faster......
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.0
ok... here is how I factor it and it works every time given \[ax^2 + bx + c = 0\] multiply a by c in your question 6 times 2 = 12 find the factors of 12 that add to 13....12, 1 then you have (ax + factor1)(ax + factor 2) (6x 12)(6x 1)   = 0 a 6 find the common factors in the numerator 6(x 2)(6x 1) = 0  6 cancel the common factors leaves (x 2)(6x 1) = 0 easy to solve
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
like I said earlier, use whatever works for you. This problem is beyond factoring......
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
kindly, can we stick with these steps.... {Differentiate} {Set f '(x) = 0} {Factor} {solve to get the critical numbers} btw I did utilize the steps above
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
yes i used that too. i mea im fine with everything except factoring now.
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
i know it was a basic thing we have to know but i forgot. so I'm trying to find an easy way to learn.
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
well I like to use slide and divide
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
i never used that technique before
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
look it up, you will find many videos on it on youtube. good luck. factoring gets easier over time.
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
thanks :)
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@precal
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
i put the answer: [1,4] max=65 min= 11 and for [0,2] max= 196 min= 11 what's wrong with the answer?
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
@dan815
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
somebody help pls!
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
are you looking for absolute max or absolute min? are you looking for global or local max or min? seems like you are doing something else other than looking for critical numbers
 one year ago

precal Group TitleBest ResponseYou've already chosen the best response.1
gotta go will help you tomorrow, it is very late for me at the moment (past 2 am)
 one year ago
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