# Math Help - Vector field in polar coordinates

1. ## Vector field in polar coordinates

I'm given ${\bold F}(r,{\theta}) = f(r,{\theta}){\bold u}_r + g(r,{\theta}){\bold u}_{\theta}$ where ${\bold u}_{\theta}$ and ${\bold u}_r$ are unit vectors.

${\bold u}_r = \cos\theta{\hat i}+ \sin\theta{\hat j}$

${\bold u}_{\theta} = -\sin\theta{\hat i}+ \cos\theta{\hat j}$

How do I rewrite ${\bold u}_r$ in vector form?

2. ## Re: Vector field in polar coordinates

okay, I just realized this is much easier than I thought. ${\v u}_r = < \cos\theta , \sin\theta >$