B3. (a) Find dy * dx and dx dx of y=x + (b) A company designed a new product with the shape of an equilateral triangular prism which is shown in Figure B3. The costs of package are 3 cents/cm for the surface of triangle side and 2 cents/cm for the surface of rectangle side. The volume of the product is 34.64 cm. 60 X 360 Figure B3 (i) Express the volume of the product in terms of x and I. (Hint: Area of triangle = ab x sine) dc (iv) Find and dx dc dx. (3 marks) (ii) Express I in terms of x. (iii) Let C be the Costs of package for the surface of a product and (4 marks) in terms of x only, show that C = x + 480 cents/cm. x (1 marks) (2 marks) (4 marks) (v) Determine the value of x and state it is maximum or minimum (6 marks) value of the function.