The top and bottom margins of a poster are each 12 cm and the side margins are each 8 cm. If the area of printed material on the poster is fixed at 1536 cm^2, find the dimensions of the poster with the smallest area.

4 answers

Let the width of the image (excluding margins) be x, then the height is 1536-x.

The total area of the poster,
A(x)=(x+2*8)(1536/x+2*12)

Differentiate with respect to x, equate to zero and solve for x. I get x=32.
Is there anything that you don't follow?
48
Width=48
height=32