# Math Help - find derivative of this equation

1. ## find derivative of this equation

This question may not belong here but it is a simple derivative question including vectors.

$\vec{r} = a\sin(\omega t) \hat{x} + b\cos(\omega t) \hat{y}; \:\:\: \hat{x}, \hat{y}$ are unit vectors

$(\vec{r})^\prime = ?$

I have a couple questions:

1) is the derivative of sin(wt), cos(wt), or do I do something extra with the angle in the parenthesis?
2) is the unit vector x considered a function? and if so what is it's derivative? I would assume $\hat{x}^\prime = 1$

2. You do need to use the chain rule $\dfrac{d}{dt} \cos(\omega t) = -\omega \sin(\omega t)$

Unfortunately, I do not know vector calculus

3. thanks!

But I have no idea what to do with the unit vector x?

4. Originally Posted by jayshizwiz
thanks!

But I have no idea what to do with the unit vector x?