An open box is made from a square lamina of side 12cm, by cutting equal squares at the corners and folding up the remaining flaps. The volume of this box cannot be
130 c.c.
Volume of box V=(12−2x)2x
V=(144+4x2−48x)x
V=4x3−48x2+144x
For maximum volume, dvdx=0
d(4x3−48x2+144x)dx=012x2−96x+144=0x2−8x+12=0⇒x=2 or 6x≠6so x=2for x=2V=(12−2×2)2×2Vmax=128So V=130 c.c