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-1.86t^{2}.

a.) find the average velocity for the given time intervals...

i.) (1,2)

ii.) (1,1.5)

iii.) (1, 1.1)

iv.) (1, 1.101)

v.) (1,1.001)

b.) find the instantaneous velocity when t=1.

please help and show steps to get your answer please!!!