Help me plz
A farmer with 12,000 meters of fencing wants to enclose a rectangular plot that borders on a straight highway. If the farmer does not fence the side a long the highway, what is the largest area that can be enclosed?

Question

Help me plz
 A farmer with 12,000 meters of fencing wants to enclose a rectangular plot that borders on a straight highway. If the farmer does not fence the side a long the highway,  what is the largest area that can be enclosed?

anonymous · Answer

11,000 meters of fencing i think

zepdrix · Answer

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Ok so we have Area (the thing that we want to maximize), in terms of ONE variable. From here we are able to easily differentiate A without worrying about any prime terms popping out.
Why would we want to find the derivative of A? Because we can find critical points related to the area. Maximum and minimum areas.
We'll set A' = 0 and find our critical points!