- #1

dumguy

- 12

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There is a time delay of 0.75 secondsbetween the time the driver sees the sign and when the driver can begin to slow down. This is called the "driver reaction time". During this reaction time the distance d, in m, traveled by the car is given by the equation d=18t, where t is the time in seconds from when the driver sees the bus. When brakes are applied, after the 0.75 second reaction time, the distance d traveled by the car in time t is given by the equation d=-3t^2+22.5t-1.6875. After the brakes are applied it takes 3 seconds for the car to come to a stop. These 3 seconds plus the 0.75 second driver reaction time means the car stops 3.75 seconds after seeing the school bus.

i) Write a piecewise-defined function to describe the distance traveled by the car until it stops.iv)how far does the car travel befor it stops?Explain how you found this.

d=(18t, 0<=t<=0.75

(-3t^2+22.5t-1.6875, 0.75<t<=3.75

When I solve the equations individually and add them together, I get 13.5+38.8125=53.3125

When I graph the piecewise on graphing calculator, I get a graph with an end coordinate of

(3.75, 40.5). How is this possible and which one is correct?