Radial Vector in Cartesian form

Click For Summary

Discussion Overview

The discussion revolves around expressing the radial vector ##\hat{r}## in Cartesian coordinates using the unit vectors ##\hat{x}## and ##\hat{y}##. Participants explore the conditions under which certain expressions hold and the definitions of the notation used.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that ##\hat{r}## can be expressed as ##\frac{\hat{x} + \hat{y}}{\sqrt{2}}##, but this is conditional on ##x=y\ge 0##.
  • Others argue that the general form of ##\hat{r}## is ##\hat{r} = \frac{x\hat{x} + y\hat{y}}{\sqrt{x^2+y^2}}##, applicable when ##\sqrt{x^2+y^2}>0##.
  • A participant questions the meaning of the notation "##\hat{}##", asking if it indicates vectors of length 1 or just vector variables.
  • Another participant provides an example of an electric field expressed in terms of ##\hat{r}## and seeks to transform it into Cartesian coordinates.
  • Clarifications are made regarding the definition of ##\hat{r}## as a unit vector.
  • There is a correction regarding the notation of vector ##\vec{d}##, with one participant acknowledging a mistake in its representation.

Areas of Agreement / Disagreement

Participants express differing views on the expression of ##\hat{r}##, with no consensus reached on a single definition or form. The discussion includes both agreement on the general form and conditions for specific cases.

Contextual Notes

Participants have not fully resolved the implications of their definitions and conditions, and there are dependencies on the specific context of the variables involved.

Arman777
Insights Author
Gold Member
Messages
2,163
Reaction score
191
If I wanted to write ##\hat{r}##in terms of ##\hat{x}##and ##\hat{y}##, is it ##\frac{\hat{x} + \hat{y}}{\sqrt{2}}## ?
 
Physics news on Phys.org
Arman777 said:
If I wanted to write ##\hat{r}##in terms of ##\hat{x}##and ##\hat{y}##, is it ##\frac{\hat{x} + \hat{y}}{\sqrt{2}}## ?
Only if ##x=y\ge 0##.
In general ##\hat r= \frac{x\hat x + y\hat y} {\sqrt {x^2+y^2}}## for ##\sqrt {x^2+y^2}>0##.
 
  • Like
Likes   Reactions: Arman777 and PeroK
tnich said:
Only if ##x=y\ge 0##.
In general ##\hat r= \frac{x\hat x + y\hat y} {\sqrt {x^2+y^2}}## for ##\sqrt {x^2+y^2}>0##.
... as

1) ##\vec r= x\hat x + y\hat y##

2) ##\hat r = \frac{\vec r}{|\vec r|}##

3) ##|\vec r| = \sqrt{x^2 + y^2}##
 
  • Like
Likes   Reactions: Arman777
Thanks
 
Arman777 said:
If I wanted to write ##\hat{r}##in terms of ##\hat{x}##and ##\hat{y}##, is it ##\frac{\hat{x} + \hat{y}}{\sqrt{2}}## ?

What does the "##\hat{}##" in your notation signify? Is it only to indicate that variables are vectors? - or does it indicate vectors of length 1?

What is your definition of ##\hat{r}##?
 
I found an E field in the form of ##\vec{E} = C(\frac{1} {|\vec{r}|} - \frac{1} {|\vec{r} - \vec{d}|})\hat{r}## where C is a constant.

I need to transform this into x,y coordinates. So I wrote

##\vec{E} = C(\frac{1} {\sqrt{x^2 + y^2}} - \frac{1} {\sqrt{(x-d)^2 + (y)^2)}}) \frac{x\hat{i} + y\hat{j}}{\sqrt{x^2 + y^2}}##
 
Last edited:
Arman777 said:
I found an E field in the form of ##\vec{E} = C(\frac{1} {|\vec{r}|} - \frac{1} {|\vec{r} - \vec{d}|})\hat{r}## where C is a constant.

I need to transform this into x,y coordinates. So I wrote

##\vec{E} = C(\frac{1} {\sqrt{x^2 + y^2}} - \frac{1} {\sqrt{(x-d)^2 + (y-d)^2)}}) \frac{x\hat{i} + y\hat{j}}{\sqrt{x^2 + y^2}}##

It looks like you have ##\vec d = (d, d)## there.
 
Stephen Tashi said:
What does the "##\hat{}##" in your notation signify? Is it only to indicate that variables are vectors? - or does it indicate vectors of length 1?

What is your definition of ##\hat{r}##?

##\hat r## is a unit vector.
 
PeroK said:
It looks like you have ##\vec d = (d, d)## there.
my mistake ##\vec{d} = d\hat{i}##
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 19 ·
Replies
19
Views
4K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 14 ·
Replies
14
Views
4K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 9 ·
Replies
9
Views
1K