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mathcalculus
 one year ago
help with optimization! (attached)
mathcalculus
 one year ago
help with optimization! (attached)

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mathcalculus
 one year ago
Best ResponseYou've already chosen the best response.0okay i understand everything..... except how to find the minimum!

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2are you familiar with derivative?

mathcalculus
 one year ago
Best ResponseYou've already chosen the best response.0i know they got the equation. y=6x+(21000/x)

mathcalculus
 one year ago
Best ResponseYou've already chosen the best response.0then after i'm not sure how they got: Minimum occurs at 59.16 ft for the length (found on a graphing calc) width: 10500/59.16 = 177.5 ft Perimeter = 710 ft

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2ok, well the method they got the minimum is just by using a graphing calculator with a max min function on it doing it manually would involve finding the first derivative of the equation and then setting it equal to zero and then solving for L

mathcalculus
 one year ago
Best ResponseYou've already chosen the best response.0is there a way to do that without it?

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2without the graphing calculator? or without having to do it manually?

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2by hand would involve finding the first derivative of the equation and then setting it equal to zero and then solving for L

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2because the slope at the minimum point is zero

mathcalculus
 one year ago
Best ResponseYou've already chosen the best response.0im doing it wrong, even on calculator :/ I'm not getting it.

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2\[y = \frac{21000}{x} + 6x\] \[y' = \frac{21000}{x^2} +6\] \[y' =0\] \[0=\frac{21000}{x^2} +6\] solve for x hopefully i didnt screw up the derivative

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2\[\frac{1}{x} = x^{1}\]

Psymon
 one year ago
Best ResponseYou've already chosen the best response.0@completeidiot derivative is fine :3

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2im just pointing out the identity that allows you to use the "power" rule for derivatives

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2\[y= x^n\] \[y' = nx^{n1}\]

mathcalculus
 one year ago
Best ResponseYou've already chosen the best response.0im not getting that. i got up to here: y=621000/x^2 then set it to 0

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.21/x is not part of the problem you can ignore it if you want its just that the identity is sometimes not obvious to other people

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2once you set it equal to zero 0=621000/x^2 just solve for x

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.26= 21000/x^2 x^2= 21000/6 x = sqrt {21000/6}

completeidiot
 one year ago
Best ResponseYou've already chosen the best response.2any other questions? sorry for any confusion i may have caused
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