Question

you have 100 ft of fencing to use for three sides of a rectangular fence, with your house enclosing the fourth side. the area of the enclosure is given by A=-2x^2+100x. graph the equation to find the maximum area possible, and how long each side needs to be to obtain that area?

Answer 1

diffrentiate the area function derivative(-2x^2+100x)=-4x+100
equate this to zero we find x=25
this is only solution so it must be maximum
sides are 25,50 area is 1250 sq.ft

Answer 2

thank you very much!
although i do need to learn more about derivatives, because i don't really understand how to get the -4x+100 part.