Derivative of r-hat with respect to theta in cylindrical coordinates

[khfrekek1992]

Homework Statement

Does anyone know what d(r-hat)/d(theta) in Cylindrical coordinates is?

Homework Equations

The Attempt at a Solution

I'm pretty sure its -(theta-hat) but I'm not sure, any help?

Thanks so much

 

[khfrekek1992]

so theta is moved over by d(theta) shifting over r-hat and theta-hat.. What would d(r-hat)/d(theta) be?

 

[khfrekek1992]

anyone? :)

 

[I like Serena]

Hi khfrekek1992!

$${d\hat r \over d\theta} = \hat \theta$$

If you draw $\hat r$ for 2 angles, you'll see that the vector-difference between them points in the direction of $\hat \theta$.
Its (approximate) length is $d\theta$.

 

[khfrekek1992]

Oh! I see how you get that now.. Thanks so much! That helps a ton :D