Question
A square piece of 30 cm is to be made into a box without top by cutting a square from each corner and folding up the flaps to form a box. What should be the side of the square to be cut off so that volume of the box is maximum?
Solution
Let x (0 < x < 15) be the length of each side of the square which is to be cut from corners of the square tin sheet of each side 30 cm. Let V be the volume of the open box formed by folding up the flaps.
But x = 5 is the only extreme point
But x = 5 is the only extreme point
