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Question related proportionality Answered

How to find out if any two quantities obey the inverse square law?

How to find out if a value 'y' is inversely proportion to 'x' or it is inversely proportional to the square of 'x'?

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steveastroukBest Answer (author)2013-03-06

Wisaam,
What you are studying is called CURVE-FITTING, and is a very interesting process. Try a search on the topic and see if it helps.

To answer your question, I would use LOGARITHMS.

Try it. Make a function Y=1/X and Y=1/X^2 and Y=X^2.

Plot them over several values of X.
Using a calculator, plot LOG(Y) and LOG (X).

Report back.

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Wisaam (author)steveastrouk2013-03-06

Thanks steveastrouk,

You have been of tremendous help to me lately, I will find as much I can about curve fitting, I actually I just now have read an article about it on wikipedia and I think I understand it now.

I had to ask, suppose that the shape of a graph is a uniform curve, the equation that I have come up with for it is

Y = MX^2 + C

where M = delta Y / delta X^2

it has worked well for me so far, but is there any other equation for a uniform curve?

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steveastrouk (author)Wisaam2013-03-06

There are an infinite number !

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bwrussell (author)2013-03-06

You've posted a lot of math questions lately, are you using Instructables to do your math homework? If so a tutor may be a better choice. It's hard to explain some things remotely, particularly when a graph is involved, and a tutor will be much quicker than posting here. Your school can probably arrange for a tutor after school or possibly even during school.
At the very least posting these questions on a homework or math centric forum will probably yield better results.

If you have the function it should be pretty obvious. If you have the values plot them.

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Wisaam (author)bwrussell2013-03-06

I am actually interested in Physics, it is not related by any aspect to my school studies. I was searching for general relativity and cause of gravity and stuff which involved a lot of graphs and math.Many people on instructables asked that why don't you consult your teacher but I said it then and I am saying it now that IT IS NOT RELATED TO MY SCHOOL STUDIES.I am just kind of curious in stuff like this. That's why I was searching for questions related to math and also used instructables. I asked this question because newton's law of gravity suggested that the gravitational force is inversely proportional to the square of the distance between two bodies. I was just wondering that why inversely proportional to 'square' of the distance, why not just distance.

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bwrussell (author)Wisaam2013-03-06

I wasn't suggesting that asking about school work here was bad. I just was making a suggestion based on a number of questions you've asked recently. If you are interested in physics, feel free to continue to ask questions but, taking a physics course or two will give you a much more rounded understanding, If you don't have ready access to a physical course then check out The Khan Academy on Youtube. They have 188 lectures under physics alone and over 3,000 total. The two physics playlists are HERE, and HERE.

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Wisaam (author)bwrussell2013-03-06

Thanks,

I will check them out, and sorry if you felt offended.

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