Can Any one help me with this question? I have a exam tomorrow..

Q) A rectangular sheet of metal measuring 120cm by 75 cm has equal squares of side x cut from each of the corners. The Remaining flaps are then folded to form an open box. Find the value of x such the volume is a maxim.

Thanks in Advance !!

Question

Can Any one help me with this question? I have a exam tomorrow.. 

Q) A rectangular sheet of metal measuring 120cm by 75 cm has equal squares of side x cut from each of the corners. The Remaining flaps are then folded to form an open box. Find the value of x such the volume is a maxim.

Thanks in Advance !!

anonymous · Answer

|dw:1339963530774:dw|
volume of the box will be = (120-2x)*(75-2x)*x=
=9000x-240x^2-150x^2+4x^3=4x^3-390x^2+9000x
to find the maximum value of this function, find 1º derivative and look for values of x which make it 0. If need more help tell me, :)