If a rock is thrown upward on the planet Mars with a velocity of 10 m/s, its height in meters t seconds later is given by y = 10t - 1.86t².

(a) Find the average velocity over the given time intervals:

(i) [1, 2] 

(ii) [1, 1.5]

(iii) [1, 1.1] 

(iv) [1, 1.01]

(v) [1, 1.001]

(b) Estimate the instantaneous velocity when t − 1.