Originally Posted by

**drew.walker** I have a problem for uni that I don't really know how to approach. The problem is:

"The velocity of a particle at time *t* = **v**(*t*) = sin*t***i** + cos*t***j** - 10*t***k**. What is the particle's acceleration, **a**(*t*) = *d***v**/*dt* as a function of time? Given that at *t* = 0 the particle is at (1,0,0), find its position at time *t*."

I understand the relationship between position, velocity and acceleration. i.e. - If **x**(*t*) is the position at time *t*, then the velocity **v**(*t*) = *d***x**/*dt* and the acceleration **a**(*t*) = *d***v**/*dt*. What I don't understand is how to treat the i, j and k in the expression? Just for my own sanity I'm thinking of *t* like I'd usually think about an *x* variable, but are i, j and k supposed to be treated as constants? If they didn't exist, I'd have no problem integrating/differentiatiating, but their occurence has completely thrown me off. Any help would be greatly appreciated.