4. 15 marks) On Monday throllgh to Friday, the Toronto Stock Exchange (TSX) has trading hollrs from 9:30 am to '1:00 prn. Sllpposc that, at timc t, the price of a stock in thc TSX on a day in November is given by: s(t) = '18 + sin (7rt2) , whcrc t is in 11011rs and time t = O represents 9:30 am. (a) Use thc substitlltion rllle to find s (t) dt. (b) 'I'he average vallic of a continuoll.s fllnction f on la, b) is given by where F(t,) average price of thc stock from 10:30 am to 2:30 prn on thc day of trading. Determine thc