12.2 Find the #27 which each largest open intervals on function is concave upward or concave downward and find the location of any points of inflection. FCX ) = X' + 4 1 X 2 - 6 x +3 Find all critical numbers of the functions, Then use the second - derivative On each critical number to determine whether 43 it leads to a local maximum or minimum f ( x ) = x t