An open metal tank of square base has a volume of 157 m3 Given that the square base has sides of length xx metres, find expressions, in terms of xx, for the following. a) Describe the height of the...

Find the first derivative

S′(x)=

and given that the surface area is a minimum, find the value of xx. Therefore,

x=  (give your answer to 2 decimal places)

Find the second derivative

S′′(x)=

Check this is a minimum.

Substitute your value for xx into S″(x) and determine whether is it a minimum.

Type 'Y' for yes, 'N' for no, or 'U' for undefined.

Hence, calculate the minimum area of metal used

Amin=   (give your answer to 2 decimal places)