I'm reviewing for my calculus exam on Tuesday and am a bit stuck on this problem. I must be differentiating something wrong.

The position vector of a particle is r(t). Find the requested vector.

Find the velocity vector at time (t)=0,

Derivative of i component:

Derivative of j component:

Derivative of j component:

- +

Shouldn't v(0)=0 ?

What am I doing wrong?