Assume a is not divisible by 10. (otherwise the problem is trivial).
<span>Define R(m) to be the remainder of a^m when divided by 10. </span>
<span>R can take on one of 9 possible values, namely, 1,2,...,9. </span>
<span>Now, consider R(1),R(2),......R(10). At least 2 of them must have the sames value (by the Pigeonhole Principle), say R(i) = R(j) ( j>i ) </span>
<span>Then, a^j - a^i is divisible by 10.</span>
What show exactly? please update.
The concept of historical cost in accounting involves valuing business resources at their purchase price. This is further explained below.
<h3>What is the historical cost?</h3>
Generally, historical cost is a value of measure used in accounting that records the value of an asset on the balance sheet at its original cost when purchased by the firm.
In conclusion, valuing business resources at their purchase price is what historical cost is about.
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