Math Is Fun Forum

Aartt

Member

Registered: 2010-12-14

Posts: 136

Ratio

I know this might sound wierd but i dont know what ratio is !!!!!! plz help

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Ratio

Hi;

Try these!

http://www.mathsisfun.com/numbers/ratio.html

http://www.mathsisfun.com/ratio2.html

http://www.mathsisfun.com/definitions/ratio.html

http://www.purplemath.com/modules/ratio.htm

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Ratio

thanks and do you understand polynominals i dont get these pages http://coolmath.com/prealgebra/15-intro-to-polynomials/   plz help me

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Ratio

Hi;

Polynomial" is a pretty big word, but it's not a hard thing.  (We use big words in math so other people think we are smart.

Try this:

http://www.mathsisfun.com/algebra/polynomials.html

Here is my favorite poly:

It has a finite number of terms in this case 5 terms:

The powers are whole numbers of 0,1,2,3,4...

There is no division that involves one of the variables.

Why do we study polynomials? Because they are easy to compute values of ( there is a nice trick ). They are easy to differentiate and integrate. It is relatively easy to find the roots. Easy to find the maxima and minima. It is easy to use them for curve fitting and approximating other functions. They solve combinatorics problems easily. In short they are everywhere in math.

Any questions?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Ratio

when do you know when you have to subtract or add like on this problem? http://www.mathopolis.com/questions/a.php?id=345&ansno=1896&site=1

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Ratio

hi Aartt,

I have looked at this site and it says you got the wrong answer.  So I need to know what answer you had.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Ratio

I got the bottom left

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Ratio

hi Aartt,

How was the vacation? 

The streets here are still full of snow.

Now to business.

Here's the problem:

Subtract (-3x² + 5y - 4xy + y²) from (2x² - 4y + 7xy - 6y²)

So you have to start with the second expression and take away the first.

There are lots of + and - terms so it is safest to put the second expression in brackets.  Thus

2x² - 4y + 7xy - 6y² - (-3x² + 5y - 4xy + y²)

Notice that there is a minus outside the bracket at this stage.

Because -- makes +    and   -+   makes -  when I clear the bracket all the internal signs change.

2x² - 4y + 7xy - 6y² + 3x² - 5y + 4xy - y²

As I moved each term beside its 'partner' I took the sign along too.

2x² + 3x² - 4y - 5y + 7xy + 4xy - 6y²  - y²

Now when you tidy up the terms the required answer emerges

5x² - 9y + 11xy - 7y²

My advice with these is to take four lines; don't try to do them in your head.

so (i)  write with a bracket     (ii)  clear the bracket and change the signs as necessary  (iii) collect like terms carrying the sign with the term  (iv) simplify

Hope that helps

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Ratio

A ratio is like 3.
Say a frozen round lake is 3 miles around the edge.
Then it is about one mile across the middle (diameter), going straight across.
So the ratio is 3 to 1.
Expressed as:     3:1

The actual number is 3.141592653589793238462643383279502884197169399... instead of 3.

A ratio is almost like a fraction or dividing two things, it is a comparison.

Say one person has two bikes, and one friend has zero bikes.  Then the ratio of bikes is 2 to 0.

2:0

Be careful with zeros though.  Some people get mad at zeros.

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igloo myrtilles fourmis

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Ratio

Bundy why did you switch around the two big equations in the start?

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Ratio

hi Aartt,

The question is worded that way.

Subtract (-3x² + 5y - 4xy + y²) from (2x² - 4y + 7xy - 6y²)

Subtract A from B = B - A

If I had a bag of apples and the question was take three apples from the bag, you would have to do:

(start with a bag of apples) and take (three away).

You have to read each question carefully to decide what calculation is being asked for.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob