Mal ,'Our Mrs. Reynolds'
[NAFDA] Spike-centric discussion. Lusty, lewd (only occasionally crude), risque (and frisque), bawdy (Oh, lawdy!), flirty ('cuz we're purty), raunchy talk inside. Caveat lector.
Well, shit, this has them all costing the same. I suck.
Just remember, PC, the world hasn't lost a biological researcher, it's gained one less way for someone to say "whoops, forget that conclusion I announced to the world press yesterday, I did the math wrong."
P-C, you missed the part that said that the base is a square.
I'm confused, then. Then there are only two possibilities, right? That the base is is either 2 x 2 or 1 x 1? And the base is automatically the top and bottom? So all you do is try out both possibilities?
20(2)(2) + 40(2)(2) = 240
20(1)(1) + 40(1)(8) = 340
I won!
(I saw the square thing before, but I didn't think THAT'S what it meant, because it made the problem way too easy.)
P-C, you missed the part that said that the base is a square.
And the part that said the box has to be big enough to contain three spherical cows.
Anyway, I agree that the question really is, "find the dimensions that results in the minimal cost, using differential calculus to show why your answer results in the minimum." Even if the question doesn't say that exactly, it's implied by virtue of being on the test at this time.
Then there are only two possibilities, right? That the base is is either 2 x 2 or 1 x 1? And the base is automatically the top and bottom? So all you do is try out both possibilities?
Who said that the sides had to be integers? 4 x 4 x 1/2 or 3 x 3 x 8/9 or any of an infinite number of others would get a volume of 8 cubic feet, too.
I'm confused, then. Then there are only two possibilities, right? That the base is is either 2 x 2 or 1 x 1?
eta xposty...
That's assuming the answer is in whole numbers. (Too lazy to go back to the question and see if that assumption is stated.)
Anyway, if I were writing the question, I'd make it so it'd be much harder to guess in this way. Or else include the "using differential calculus, show why this is so" part.
Who said that the sides had to be integers?
Yeah, I just realized that. Oooops.
So that makes x=y.
(x^2)z = 8
20x^2 + 40xz
160/z + 320/x
Aaaand, yeah, I forgot how to do calculus.
Brain hurty, go play with pretty words now. Sweep numbers into pile and leave for odd people to play with.
OK, P-C:
x^2 * z = 8
z = 8/x^2
C(x) = 20x^2 +40 xz = 20x^2 + 320/x
C'(x) = 40x - 320/x^2
To find the minimum, find where the derivative is 0.
0 = 40x - 320/x^2
320/x^2 = 40x
8 = x^3
2=x
Ooooh yeah. Now I remember that shit. Thanks!
Ooooh yeah. Now I remember that shit. Thanks!
t I think they're "speaking" gibberish and hoping the rest of us will think it makes sense. I've got a better chance of understanding Xhosa