Question

derive v=4x^3 -200x^2 +2400x
I have derived it to v'=12x^2 -400x +2400
But now i need to solve for the value of x

Answer 1

did they give a value of v and v'?

Answer 2

no

Answer 3

but the book seems to think that the answer is 7.85 i have no clue how it got that

Answer 4

what's the full question?

Answer 5

uhhh, the question is hold on

Answer 6

one sec

Answer 7

The volume of an open box is given by the formula v(x)=x(60-2x)(40-2x) where x is the length in centimetres of a square cut out of each corner of a sheet of cardboard 60cm long and 40cm wide.
a) find the possible values of x
b) what value of x gives the max maximum volume give your answer to 2 decimal places
C what is this maximum volume?