Posted by DUE TOMORROW NEED HELP! on .
The sum of x and y is 8. What is the maximum value of xyx^2?
Please help!

AP Calculus AB 
Damon,
f = x (yx)
but y = 8x
so
f = x (82x) = 8x  2x^2
df/dx = 8  4 x
zero when x = 2
Posted by DUE TOMORROW NEED HELP! on .
The sum of x and y is 8. What is the maximum value of xyx^2?
Please help!
f = x (yx)
but y = 8x
so
f = x (82x) = 8x  2x^2
df/dx = 8  4 x
zero when x = 2