Is the Equation x^{a^b} = (x^{a^{b-1}})^a True for All Natural Numbers?

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In summary, the conversation discusses whether the equation x^{a^b} = (x^{a^{b-1}})^a is true for all natural numbers. The proof provided shows that it is true using exponent laws. There is also a mention of the ambiguity surrounding whether zero is considered a natural number.
  • #1
notnottrue
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Hi,
If all x,a,b and c are all natural numbers, is this true?
[itex] x^{a^b} = (x^{a^{b-1}})^a[/itex]
Proof
if [itex] c = a^{b-1}[/itex]
[itex] ca = (a^{b-1})a = a^b [/itex]
and [itex] (x^c)^a = x^{ca} = x^{a^b} [/itex]

Could I please have some feedback on this,
Thanks
 
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  • #2
There is no universal agreement on whether zero is a natural number. You are going to need write "positive integer" or deal with the case when one or a number of the variables are zero separately.
 
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  • #3
notnottrue said:
Hi,
If all x,a,b and c are all natural numbers, is this true?
[itex] x^{a^b} = (x^{a^{b-1}})^a[/itex]

Yes, and the proof doesn't require any substitutions either. Simply following your exponent laws,

[tex]\left(x^{a^{b-1}}\right)^a[/tex]
[tex]=x^{a^{b-1}a}[/tex]
[tex]=x^{a^{b-1+1}}[/tex]
[tex]=x^{a^b}[/tex]
 

FAQ: Is the Equation x^{a^b} = (x^{a^{b-1}})^a True for All Natural Numbers?

What is a double exponent?

A double exponent is a mathematical expression that involves two exponents. This can be written as a^b^c, where a is the base, b is the first exponent, and c is the second exponent.

How do you simplify a double exponent?

To simplify a double exponent, you must use the power rule, which states that (a^b)^c = a^(b*c). This means that you multiply the two exponents together and keep the same base.

Can a double exponent be negative?

Yes, a double exponent can be negative. This occurs when one or both of the exponents are negative. For example, (2^-3)^-2 would result in 2^6, which is equal to 64.

What is the difference between a double exponent and a power tower?

A double exponent is a specific type of power tower, where there are two exponents involved. A power tower can have any number of exponents, but a double exponent specifically has two.

What are some real-world applications of double exponents?

Double exponents are often used in physics and chemistry to represent quantities such as energy and radioactive decay. They are also used in computer science and cryptography to represent large numbers and perform complex calculations.

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