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# what is the value?

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Intern
Joined: 11 Jun 2010
Posts: 14

Kudos [?]: 53 [0], given: 0

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19 Dec 2010, 08:17
5^-5 - 5^-12 = ?

how do we interpret negative exponents in this case?

Kudos [?]: 53 [0], given: 0

Math Expert
Joined: 02 Sep 2009
Posts: 41892

Kudos [?]: 129166 [0], given: 12194

Re: what is the value? [#permalink]

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19 Dec 2010, 08:28
smitakokne wrote:
5^-5 - 5^-12 = ?

how do we interpret negative exponents in this case?

Negative exponents: $$a^{-n}=\frac{1}{a^n}$$.

So, $$5^{-5}-5^{-12}=\frac{1}{5^5}-\frac{1}{5^{12}}=\frac{5^7-1}{5^{12}}$$.

For more check Number Theory chapter of Math Book: math-number-theory-88376.html
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Kudos [?]: 129166 [0], given: 12194

Re: what is the value?   [#permalink] 19 Dec 2010, 08:28
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