If you notice the picture below, the amount of fencing, or perimeter, that will be used will be 3w + 2l
now
solve for "w", to see what critical points you get, and then run a first-derivative test on them, for the minimum
notice the
so. you can pretty much skip that one, though is a valid critical point, the width can't clearly be 0
so.. check the critical points on the other
now
solve for "w", to see what critical points you get, and then run a first-derivative test on them, for the minimum
notice the
so.. check the critical points on the other