My class is doing a test review for homework, and I was doing well so far until I bumped into this:

A particle moves along the x-axis in such a way that its acceleration at time t for t (greater than or equal to) 0 is given by a(t)=2 cos(t). At time t=0, the velocity of the particle is v(0)= -1 and its position is x(0)= 0.

a. Write an equation for the velocity for the velocity v(t) of the particle.

Already found this, it was: v(t)=2 sin t -1

b. Write an equation for the position x(t) of the particle.

Found this also, which was: x(t)= -2 cos t - t +2

c. For what values of t, 0< t <

, is the particle at rest? (less thans are less than or equal to).

The problem I have with this is isolating t using: -1= -2 cos t - t +2

to find when the particle is at rest, set v(t) = 0, not x(t).

I already did a similar problem, but it was much simpler to isolate t to one side and solve for it. (2

-2

sin 2

t = 0 ----> t=0.25)

Another little question while I'm on the subject, how do I

I'm too used to single terms.

chain rule ...