Question

Need help with solving an optimization problem (calculus)

Answer 1

any idea?

Answer 2

@TuringTest

Answer 3

yup thats exactly what i got

Answer 4

xy=162 so solve for y, plug into the cost equation, differentiate, set equal to zero, solve for x.

Answer 5

i drew the picture and i got c(x)=20x+10(x+2y)

Answer 6

x=162-20y/30?

Answer 7

Where'd you get that?
y = 162/x

Answer 8

oh that was a step ahead

Answer 9

i already did the y=162/x

Answer 10

Now substitute that in, in place of y in
c(x)=20x+10(x+2y)
then differentiate

Answer 11

ok differtiated i got 30?

Answer 12

20+10=30

Answer 13

You did something wrong, or didn't plug in y\[\Large c(x)=20x+10(x+\frac{ 324 }{ x })\]

Answer 14

yup and i distributed

Answer 15

i will be back in an hour

Answer 16

\[\Large c(x)=20x+10x+\frac{ 3240 }{ x })\] or \[\Large c(x)=20x+10x+3240 x^{-1}\]now differentiate

Answer 17

20+10-3240x^-2

Answer 18

so 30-3240x^-2

Answer 19

0 = 30-3240x^-2

Answer 20

Solve for x.

Answer 21

i got x=sqrt(108)

Answer 22

but how to i get y?

Answer 23

y = 162/x

Answer 24

oh gotcha....plug in sqrt(108) into the x value? correct?