A farmer has 2400 ft of fencing and wants to fence off a rectangular field that borders a straight river. he needs no fence along the river, what are the dimensions of the field with the largest area?
A(x) = x(2400-2x) A(x) = 2400x - 2x^2 --- You have a quadratic with a = -2 and b = 2400 ---- Maximum Area occurs where x = -b/2a = -2400/(2*-2) = 600 ft. (width) length = 2400-2x = 2400-2*600 = 1200 (length)