answer both parts please

(7%) Problem 9: One day when the speed of sound in air is 343 m/s, a fire truck traveling at Vs = 27 m/s has a siren which produces a frequency of fs = 428 Hz. Randomized Variables VS = 27 m/s f = 428 Hz Forbes, David - david forbes @doane.edu @theexpertta.com - tracking id: 9N69-72-B9-45-AB7A-36840. In accordance with Expert TA's Terms of Service, copying this information to any solutions sharing website is strictly forbidden. Doing so may result in termination of your Expert TA Account, 4 50% Part (a) What frequency, in units of hertz, does the driver of the truck hear? Grade Summary fa = 1 Hz Deductions 0% Potential 100% sinO cos() tan( 7 8 9 HOME Submissions cotan() asin acos() E 4 5 6 Attempts remaining: 1 (83% per attempt) atan( acotan() sinh() 2 3 detailed view cosh( tanh() cotanh() + 0 END Degrees O Radians VO BACKSPACE DEL CLEAR Submit Hint Feedback I give up! Hints: 0% deduction per hint. Hints remaining: 1 Feedback: 0% deduction per feedback. 4 50% Part (b) What frequency, in units of hertz, does an observer hear when the truck is moving away