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# Question related proportionality

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'?

76Views8Replies

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'?

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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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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There are an infinite number !

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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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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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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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Thanks,

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

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No worries.

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