regular co-ordinate to polar represention

shahar

shahar

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Why do we need polar representation of an object?
Why do we need to change to that represnetion, for example, in parabola?
 
shahar said:
Why do we need polar representation of an object?
Why do we need to change to that represnetion, for example, in parabola?
Click to expand...
In some situations the polar coordinate system is more convenient than cartisian. E.g. if you are operating a cannon getting an order that says "point the barrel in the A degrees direction and make the distance B km" is way easier to process than "the target is at point (X, Y), figure out what to do".

Not sure what you mean about parabolas. What's the context?
 
lev888 said:
In some situations the polar coordinate system is more convenient than cartisian. E.g. if you are operating a cannon getting an order that says "point the barrel in the A degrees direction and make the distance B km" is way easier to process than "the target is at point (X, Y), figure out what to do".

Not sure what you mean about parabolas. What's the context?
Click to expand...
The context is the finding of eccentricity of parabola.
Can you elaborate on it?
 
Last edited:
I don't have a link.
And my Question is:
why by finding eccentric formula parabola we need to use polar presentation?
 
shahar said:
I don't have a link.
And my Question is:
why by finding eccentric formula parabola we need to use polar presentation?
Click to expand...
Ok, you don't have a link, but you should have a source for the statement that we "need" to use polar coordinates. It would be helpful to see the context.
My guess: since eccentricity is a ratio of distances, we want to use a representation that involves distances. And that's the polar representation.
 
Thank you.
we mean in Hebrew the general and regular people. So, we can be any group of people like you and me as human.
 
shahar said:
Thank you.
we mean in Hebrew the general and regular people. So, we can be any group of people like you and me as human.
Click to expand...
I understand what you meant by "we". But the notion of the "need" to use a particular representation probably came from an external source, no?
 
We don't NEED to use polar coordinates to find the eccentricity but it happens that in polar coordinates there is a simple representation for all "conic sections"
\(\displaystyle r= \frac{ed}{1+ cos(\theta)}\)
where d is the distance from the origin to the directrix and e is the eccentricity.
The conic is a parabola if and only if the eccentricity is 1.
The conic is a circle if and only if the eccentricity is 0.
The conic is an ellipse if and only if the eccentricity is between 0 and 1.
The conic is a hyperbola if and only if the eccentricity is larger than 1.
 
lev888 said:
I understand what you meant by "we". But the notion of the "need" to use a particular representation probably came from an external source, no?
Click to expand...
Why? from external?
needs, I think that as in Hebrew can come from inside like the Needs Pyramid of Maslow, no? :sneaky:
 
shahar said:
Why? from external?
needs, I think that as in Hebrew can come from inside like the Needs Pyramid of Maslow, no? :sneaky:
Click to expand...
Sure, but if it came from inside (your brain), then you should know why you needed to use polar coordinates.
 
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