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What does the denominator of a rational exponent represent

2 Answers

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So here's the rule from fractional exponents to radicals:
x^{(m)/(n)}=\sqrt[n]{x^m}

Looking at this rule, the denominator represents the root.

User Mjv
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4 votes

The denominator of a rational exponent represents a root.

For example, the exponent
(1)/(2) represents a square root. Likewise, an exponent of
(1)/(3) represents a cube root.

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You can understand this if you recall what a root means, and what the rules of exponents are. A square root multiplied by itself gives the original value. Consider ...


\displaystyle\left(x^{(1)/(2)}\right)\left(x^{(1)/(2)}\right)=x^{\left((1)/(2)+(1)/(2)\right)}\\\\=x^(1)=x

For other denominator values, the number of factors that must be multiplied to get x is the number in the denominator—just as you expect for a root.