# I Length of bases in Polar coordinates

1. Jun 15, 2016

### smodak

According to this video the length of basis is r. It grows as we further from the origin . Why?

2. Jun 15, 2016

### Staff: Mentor

There is not really a "length" of it, but you can consider how far you move if you move by a small $\epsilon \hat \theta$, the length increases with the radius.

3. Jun 15, 2016

### smodak

Thanks. That makes sense. But why would the 'length' be r as Pavel Grinfeld says in the video.

4. Jun 16, 2016

### Staff: Mentor

Set $\epsilon=1$. With 2 pi you get a length of 2 pi r, with 1 you would expect a length of r. Sort of.