To three decimal places, find the value of the first positive x-intercept for the function f(x) = -2cos(x + 1).

A box is to be constructed from a sheet of cardboard that is 10 cm by 60 cm by cutting out squares of length x by x from each corner and bending up the sides.

What is the maximum volume this box could have? (Round your answer to two decimal places.)

Find the minimum value of the function f(x) = x2+ 9x - 16.