Application (10 marks) 21. Analyze the function below based on the following headings: domain, x & y intercepts, critical points and intervals of increasing and decreasing, points of inflection and intervals of concavity. Sketch the function on the grid provided. f(x) = 3x4 -12x319. Determine the intervals of concavity and the points of inection for the following function: (8 marks) f(x)=x4 +4x3 ~18x2 +12x12 20. An express railroad train between two cities carries 10,000 passengers per year for a one way fare of $50. If the fare goes up, ridership will decrease because more people will drive. It is estimated that each $10 increase in the fare will result in 1000 fewer passengers per year. What fare will maximize revenue? (6 marks)