Question

A farmer has 160 ft. of fencing and wants to fence off a rectangular field that borders a straight river. He needs no fencing along the river.

a) What are the dimensions of the field that has the largest area?

b) What is the maximum area?

Answer 1

L and B be the dimensions of field.

L+2B =2400ft.

AreaA = L×B=L×(2400-L)/2=1200L-L^2

For max.area to use the fencing dA/dL=1200-2L=0 or L=600ft

B=(2400-600)/2=900ft.

Total area = 540000ft^2.

Maybe?

Explanation:

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