SOLUTION: Last digit. Find the last digit in 3^9999.

Question 213709This question is from textbook Elementary & Intermediate
: Last digit. Find the last digit in 3^9999.
This question is from textbook Elementary & Intermediate

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Last digit. Find the last digit in 3^9999.
-----------------------
1st power last digit: 3
2nd power last digit: 9
3rd power last digit: 7
4rh power last digit: 1
5th power last digit: 3
-----------------------------
So there is a 5-step cycle
-------
9999/5 = 1999 with a remainder of 4
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So 3^(9999) = 3^(5*1999 + 4)
= (3^5)^1999 * 3^4
= 3*3^4
= 3^5
= 3
=================
Cheers,
Stan H.
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