pplication: 1. Given the function y = x +4x3+5x+16, a) determine all critical points and identify if the critical points represent a maximum, a minimum, or neither. Identify all the intervals of increase or decrease. Use a table to organize your work. (6 marks) b) determine all points of inflection and identify all the intervals where the function is concave up and concave down. Use a table to organize your work