Question

a gardner having 120m of fencing whishes to enclose a rectangular plot of land and also a erect a fence across the land parellel to two of the sides. find the maximum area he can enclose

Answer 1

3 W + 2 L = 120 ... L = 60 - 3/2 W

a = L W ... substituting ... a = 60 W - 3/2 W^2

the max is on the axis of symmetry
... Wmax = -60 / (2 * -3/2) = 20

substitute back to find Lmax , then calculate max area