# Simple Derivative Question

1. Oct 20, 2008

### possum30540

1. The problem statement, all variables and given/known data
Suppose the x coordinate of a pie is given as a function of time t by
x(t) = (u^2)(t^2) + 3ut,
where u is independent of t. Calculate (dx/dt) and (dx/du). Also, whihc one of the above derivatives (if either) give you vx, the x component of the pie's velocity?

2. Relevant equations
Just derivative rules.

3. The attempt at a solution

(dx/dt)= 2(u^2)t + 3u

(dx/du)=2u(t^2) + 3t

Since t represents tiem in this function, to obtain the velocity you must use (dx/dt).

Please let me know if this is correct or if I am missing a step.

2. Oct 20, 2008

### possum30540

I don't understand why my problem has not been answered yet while others after me have . . I have given you all the required information. Please let me know anything else you may need. Thanks.

3. Oct 20, 2008

### HallsofIvy

Staff Emeritus
No particular reason why one question will be answered and another will not. You cannot, in general, expect a question to be answer in a few minutes or even a few hours. People don't sit around waiting for questions!

It looks to me like you answers are correct.