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Why is a rational exponent an exponent in the form of a fraction?

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monique06 | Valedictorian

Posted May 22, 2013 at 4:58 PM via web

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Why is a rational exponent an exponent in the form of a fraction?

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pramodpandey | College Teacher | Valedictorian

Posted May 22, 2013 at 5:07 PM (Answer #1)

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Let x^2=3

exponent of x is 2.

We want a number ,when square it should be  3.

This means we want a square root of 3.

`x=+-sqrt(x)=+-(3)^(1/2)`

(1/2) is not an integer. It is a rational number . In some case it may be

integer.

x^2=16

x=`+-sqrt(16)=+-4`

Since integer is subset of rational number therefore it is also rational.

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ishpiro | Teacher | (Level 2) Associate Educator

Posted May 22, 2013 at 5:19 PM (Answer #2)

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A rational exponent is an exponent in form of a fraction because by definition, rational numbers are numbers that could be written as "ratios", or fractions.

This includes, obviously, fractions, such as 3/5 or 13/4, decimals (they could be converted into fractions) and integers (they could be written as fractions with the denominator 1:  5 = 5/1). All these can be positive or negative.

An example of a number that is NOT rational would be `sqrt2` , because it cannot be converted into a fraction. If you plug `sqrt2` in a calculator, you will see that this is a decimal which has infinite number of digits after the decimal point, not arranged in any kind of pattern. Such numbers are called "irrational".

So, rational exponent just means that the exponent is a rational number.

 

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