Exercise given in textbook:
A farmer has 40m of fencing with which to enclose a rectangular pen.Given that the pen is x m wide -
show that it's area is (20x - x^2)m^2
and deduce that the maximum area that he can enclose (Answer given 100m^2).
I have completed lots and lots of exercises involving completing the square- also with minimum and maximum values but am obviously missing something here.
Hi, here is the solution.
Area = 20x -x^2
Find the derivative and set equal to zero.
dA/dx = 20-2x
dA/dx=0 => 20-2x=0
A quadratic equations word problem is solved by completing the square. The solution is detailed and well presented. The response was given a rating of "5/5" by the student who originally posted the question.