Suppose that the velocity (in meters per second) for a particle moving along a line is given by the function v(t)=t^2-4t-12 on interval 1<t<7

a) Find the displacement

b) find the displacement traveled by the particle during the given time interval

ok for part a i know you have to take the anti-derivative and you get t^3/3 -4t^2/2 -12t and interval 1 to 7

[7^3-((4(7)^2)/2)-12(7) ] - [1^3/3-((4(1)^2)/2)-12(1)]

i got -194/3 meters

I'm not sure what to do about part b. And is my answer and method for part a correct?