# A poster is to contain $50cm^2$ of matter with borders of 4 cm at top and bottom and of 2 cm on each side. Find the dimensions if the total area of the poster is minimum.

Toolbox:
• For greatest area, maximise area.
• Working rule for maxima minima.
• Find the function to be maximised or minimised
• Convert the function into single variable
• Apply the conditions for maximum or minimum i.e., first derivative = 0 ( w.r.to the variable converted) and second derivative positive for minima and negative for maxima.
Let the dimensions be $x$ cm length and $y$ cm breadth.
Area of poster = $A = xy$