Talk:Vector fields in cylindrical and spherical coordinates

Predictably, there is a notation conflict. Given that the article on spherical coordinates would predictably end up getting written by mathematicians, while this one would predictably end up getting written by physicists (since mathematicians generally only use Cartesian coordinates), predictably the notations are different, causing confusion to anyone who clicks on spherical coordinates. The matter remains unresolved. Revolver 05:48, 28 August 2005 (UTC)

Description of φ in spherical coordinates
The description of φ says: "φ is the angle with the X-Z-plane". I would say "φ is the angle with the X-Z-plane with positive X" or something else, because otherwise the angle could be measured with a negative X, which gives a wrong angle. 80.32.129.34 12:06, 15 March 2007 (UTC)

Unit vector derivatives
is it correct to specifically call out the time derivative in those descriptions? would it not be more accurate to call out the spatial derivatives? i.e., in cylindrical coord's, dr_hat/dtheta = theta_hat. aren't the time derivatives only collapsed chain rules of the spatial derivative transformations? (dr/dt = dr/dtheta * dtheta/dt = dtheta/dt * theta_hat) ? —Preceding unsigned comment added by 64.203.249.10 (talk) 01:22, 28 September 2007 (UTC)

Comment by 65.95.78.112
COMMENT: I think the formula for φ is not correct as the arctan function only provides values on the (-π/2;π/2) interval. As a result, I think the best is to adapt the calculation of φ to, for instance, each quadrant ([0;π/2), [π/2;π), [π;3π/2) and [3π/2;2π)). See comment in []. —Preceding unsigned comment added by 137.111.219.14 (talk) 02:24, 14 February 2008 (UTC)

Description of unity vector in spherical coordinates
How come ρ, the magnitude of the projection of the vector on xy-plane, has a direction. It simply goes against the definition.
 * I assume you mean cylindrical coordinates as of the notations used in the article. It doesn't have a direction in the origin, but elsewhere it does. Imagine that you are looking at the point (x,y,0), and that you draw a line from the origin through the point and add an arrow to the end of the line. Then the arrow gives the direction of ρ in that point. 78.91.38.146 (talk) 13:39, 23 November 2008 (UTC)

Definition of θ and φ is absolutely wrong
θ and φ are not the angle between the "VECTOR" and the Z-axis or its projection and the X-axis. But the are the angles between the "POSITION" of the "Vector" and those axes. Actually here we are dealing with Vectors which are not that free in space ( Their position should be specified).

For example  E(0,0,0)= 3 i + 4 j + 5 k,  has a different "spherical" representation at points (0,0,0) and (1,0,0) and so on. —Preceding unsigned comment added by 118.100.167.123 (talk) 10:25, 24 June 2010 (UTC)

Symbols unclear in `2.2 Time derivative of a vector field`
Currently the text includes:
 * $$\mathbf{\dot A} = \boldsymbol{\hat r} (\dot A_r - A_\theta \dot\theta - A_\phi \dot\phi \sin\theta)

+ \boldsymbol{\hat\theta} (\dot A_\theta + A_r \dot\theta - A_\phi \dot\phi \cos\theta) + \boldsymbol{\hat\phi} (\dot A_\phi + A_r \dot\phi \sin\theta + A_\theta \dot\phi \cos\theta)$$

But it is unclear what the difference is between (for example), $$\dot{A}_\theta$$ and $$\dot{\theta}$$. Presumably $$\dot{\theta} = \frac{d\theta}{dt}$$, then is $$\dot{A}_\theta = r \dot{\theta}$$?

Even if the symbols seem trivial, it would be good to define them. Thanks!

Zhermes (talk) 00:29, 31 December 2019 (UTC)