Difference between revisions of "Proportion"

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==Direct Proportion==
 
==Direct Proportion==
Direct proportions is a proportion where one is a multiple of the other. Direct proportion between two numbers '''x''' and '''y''' can be expressed as: <br />
+
Direct proportion is a proportion in which one number is a multiple of the other. Direct proportion between two numbers '''x''' and '''y''' can be expressed as: <br />
 
<math>y=kx</math><br />
 
<math>y=kx</math><br />
 
where '''k''' is some [[real number]]. <br /> The graph of a direct proportion is always linear.
 
where '''k''' is some [[real number]]. <br /> The graph of a direct proportion is always linear.
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<math>xy=k</math><br />
 
<math>xy=k</math><br />
 
where k is some real number that does not equal zero. <br />
 
where k is some real number that does not equal zero. <br />
 +
 +
==Exponential Proportion==

Revision as of 20:20, 13 September 2007

This is an AoPSWiki Word of the Week for Sep 13-19

Two numbers are said to be in proportion to each other if some numeric relationship exists between them. There are several types of proportions, each defined by a separate class of function.

Direct Proportion

Direct proportion is a proportion in which one number is a multiple of the other. Direct proportion between two numbers x and y can be expressed as:
$y=kx$
where k is some real number.
The graph of a direct proportion is always linear.

Inverse Proportion

Inverse proportion is a proportion in which as one number's absolute value increases, the other's decreases in a directly proportional amount. It can be expressed as:
$xy=k$
where k is some real number that does not equal zero.

Exponential Proportion