NOTE: I suppose there was an error when typing the Interval.
Graphing the graph up to 99 for example for point A, implies a 10-fold perioricity and for point B almost 10 integrals! That is a little expensive!
Which implies an extremely costly graph to count the positive and negative points.
I will start by performing the procedure for a shorter interval, in case it is necessary and implicit
Extensive interval, I think the procedure is contingent and it is simply a matter of extrapolating it.
So things,
The function:
[tex]v (t) = t ^ 3 - 10t ^ 2 + 21t, [0.9][/tex]
a) [tex]t \in (0.3) \Rightarrow[/tex] Positive address & [tex]t \in (7.9)[/tex]
[tex]t \in (3.7) \Rightarrow[/tex] Negative address
b) [tex]Displacement = \int \limit ^ 9_0 (t ^ 3-10 ^ t2 + 21) dt = \frac {t ^ 4} {4} - \frac {10 ^ 3} {3} + \frac {21t^2} {2} \Big| _0 ^ 9[/tex]
Displacement = 60.75m
c) [tex]Distance = \int \limit ^ 0_3 (t ^ 3-19t ^ 2 + 21t) dt + \int \limit ^ 7_3 (-t ^ 3 + 10t ^ 2-21t) dt + \int \limit ^ 9_7 (t ^ 3-19t ^ 2 + 21t) dt[/tex]
Distance = 167.41m