1.67: x cm x cm Diagram accurately dra

4PM1/1/January/2019 — Question 7 · 10 marks

1.67 diagram 1
Figure cut form away an open shows from box. each a rectangular corner of sheet the sheet. of metal The sheet by is then folded A square along of the side dotted lines is to
The volume of the box is Vcm3\displaystyle V\mathrm{cm}^{3}
(a) Show that V=4x352x2+160x\displaystyle V = 4x3 - 52x2 + 160x
(3)
(b) Using value of calculus, gives find a maximum the value value of for of which V\displaystyle V is a maximum, justifying that this
(5)
(c) Find the maximum value of V.\displaystyle {\cal{V}}.
(2)