Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Math help plllllease?
Please help me with this one!
You have 64 feet of fencing to enclose a rectangular plot that borders on a river. If you do not fence the side along the river, find the length and width of the plot that will maximize the area.
2 Answers
- Anonymous1 decade agoFavorite Answer
2x + y = 64
solve for y
substitute the equation into formula:
A(x) = xy
do derivative.
equate it to 0.
solve for x.
get value for y.
- Anonymous1 decade ago
let y be the length of the side that is opposite of the river.
let x be the other two sides
P = y + x + x
given the perimeter is 64ft
64 = y + 2x
y = 64 - 2x
A = width * length
the dimentions, in term of s, is x by 64 - 2x
A = x (64 - 2x)
A = 64x - 2x^2
find the derivative and set it equal to 0
0 = 64 - 4x
-64 = -4x
x = 16
y = 64 - 2(16)
y = 32
so the dimentions that maximize the area is:
16ft x 32ft <== answer
hope it helps
Rec