Question

Optimization problem. Please check my work :)

Answer 1

Original Question

Answer 2

My work

Answer 3

you have an error on the 2nd page... has to do with the signs

Answer 4

okay, where? :)

Answer 5

you have the correct area equation but whn you go to take the derivative, it looks like you've factored out a negaitve sign... only you didn't factor it from both terms

Answer 6

Oh I had 16x-2x^2 and I flipped it around to get -2x^2+16x
is that where you're talking about?

Answer 7

(that's all referring to just the numerator of course)

Answer 8

no that's okay but look at what you worte in the parentheses where you're taking the derivative

Answer 9

\[(\frac{ -2x^2+16x }{ 3 })\]?

Answer 10

that's not what you've written...
\[-\frac{ 2x^2+16x }{ 3 }\]

Answer 11

oh should I just move the negative up by the 2?

Answer 12

@pgpilot326 sorry the pc got stuck xD

Answer 13

can the result have it like it is? or should I move the minus sign up by the 4x?

Answer 14

Like should they all be changed in that line? o.o or just inside the parenthesis?

Answer 15

if you leave it like it is, you've written it incorrectly. move the negative sign up (on all subsequent equations as well) or change the sign on the 16x term (on all subsequent eqns as well).

Answer 16

if you just get comfortable putting the 16x term first and let the x^2 term be second, you won't have such issues

Answer 17

haha siigh. You're right. but then I must switch the whole thing D:

Answer 18

Is the rest of the problem good and correct?