A dancer moves in one dimension back and forth across the stage. If the end of the stage nearest to her is considered to be the origin of an x axis that runs parallel to the stage, her position, as a function of time, is given by X(t) = [(0.11 m/s^3)t3^- (0.55 m/s^2)t^2 + (1.70 m/s)t - 4.50 m]i. Find an expression for the dancer's velocity as a function of time. (Assume SI units. Do not include units in your answer. Use the following as necessary: t.) v(t) = i