8. The displacement (in centimeters) of a particle moving back and forth along a straight line is given by the equation of motion s = 2 sin it + 3 cos wit, where t is measured in seconds. (a) Find the average velocity during each time period: (i) [1, 2] (ii) [1, 1.1] (iii) [1, 1.01] (iv) [1, 1.001] (b) Estimate the instantaneous velocity of the particle when t = 1