as usual, P=2(W+L)
A = WL = 150
So, L = 150/W
P = 2(W + 150/W)
for minimum P,
dP/dW = 2 - 300/W^2 = 0, so
W = √150 = 5√6
A rancher wants to build a rectangular pen with an area of 150 m^2?
a. Find an equation for the perimeter P in terms of W and L .
b. Use the given area to write an equation that relates W and L .
c. Find the pen dimensions that require the minimum amount of fencing.
Width =
Length =
1 answer
1 answer