Let F(z) = I 3-t dt for-00+% t2 +40 0 (a) Find the value of a where F obtains its maximum value. x= (b) Find the intervals over which F is only increasing or decreasing. Use interval notation using U for union and enter "none" if no interval. Intervals where F is increasing: Intervals where F is decreasing: (c) Find open intervals over which F is only concave up or concave down. Use interval notation using U for union and enter "none" if no interval. Intervals where F is concave up: Intervals where F is concave down: