Converting a Shifted Circle into Polar Coordinates

In summary, the conversation discusses how to express a circle in polar coordinates and the necessary transformations to do so. It is mentioned that four parameters are needed to describe a shifted circle in either coordinate system. However, only two variables are needed to plot a one-dimensional object in a two-dimensional space. The conversation also mentions that the transformations can be done in polar coordinates, but it is not necessary in this case as the circle is given as a constant.
  • #1
Tarhead
7
0
How do I express this in polar coordinates?

(x-h)^2+(y-k)^2= h^2+k^2

It is a circle with k and h greater than 0.
 
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  • #2
go to:

http://mathworld.wolfram.com/PolarCoordinates.html

I think the transforms would be

x--> rcos theta
y--> r sin theta
h --> R cos theta'
k --> R sin theta'

4 prameters to describe the points on a shifted circle (shifted orgin because of the k and h terms) in either cartesian or polar coordinates

Not sure, but I think.
 
  • #3
In two dimensions, the transformations are:

[tex]x = r\cos \theta, \qquad y = r\sin \theta[/tex]

That's all you need.
 
  • #4
Yeah this makes sense. Sorry for my mistake. You'll only need two variables to plot a 1-d object in a 2d space.

You would need four parameters to specify a shifted circle in either coordinate system. (The k and h parameters will propagate through your transformation.) You could transform this shift into polar coordinates as well (and you would have to if this was a complicated mechanics problem) but you don't even need to bother with this because it is given as a constant.

Hope I didn't mess you up. Sorry again.
 

1. What are polar coordinates and how are they different from Cartesian coordinates?

Polar coordinates are a way of representing a point in a two-dimensional plane using two values: the distance from the origin (called the radius) and the angle from a reference line (usually the positive x-axis). This is different from Cartesian coordinates, which use two values for the x and y coordinates of a point.

2. Why would I need to express something in polar coordinates?

Polar coordinates are useful for representing certain types of shapes and equations, such as circles and spirals, which can be difficult to express in Cartesian coordinates. They also have applications in physics and engineering, such as representing the position and direction of an object in space.

3. How do I convert from Cartesian coordinates to polar coordinates?

To convert from Cartesian coordinates (x,y) to polar coordinates (r,θ), you can use the following equations: r = √(x^2 + y^2) and θ = tan^-1(y/x). This means that the radius is equal to the square root of the sum of the squares of the x and y coordinates, and the angle is equal to the inverse tangent of the y coordinate divided by the x coordinate.

4. Can I express negative numbers in polar coordinates?

Yes, negative numbers can be expressed in polar coordinates. The radius (r) can be negative, indicating a point in the opposite direction from the reference line. The angle (θ) can also be negative, indicating a point in the opposite direction from the positive x-axis.

5. Are there any limitations to using polar coordinates?

While polar coordinates have many applications, they are not suitable for representing all types of shapes and equations. For example, they cannot accurately represent vertical or horizontal lines, and some curves may be difficult to express using polar coordinates. Additionally, certain calculations, such as finding the distance between two points, may be more difficult in polar coordinates compared to Cartesian coordinates.

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