So you need 2 widths and 1 length
2w + l = 800
l = 800-2w
area = lw =w(800-2w)
= -2w^2 + 800w
a downward parabola, with a min value at its vertex.
the w of the vertex is -800/-4 = 200 ,
( in y = ax^2 + bx + c, the x of the vertex is -b/(2a) )
so the area is 200 m by 800-2(200) or 400 m
Denzel wants to rope off a 800 m2
rectangular
swimming area using the beach as one of the
sides. What should the dimensions of the
rectangle be in order to use the minimum
amount of rope?
1 answer