SOLUTION: 1. What's the one's digit of 2003^2004? A)9 B)7 C)3 D)1 2. The value of the 100-term sum 1/2+3/2+5/2+...+195/2+197/2+199/2 is A)5000 B)10,000 C)15,000 D)20,000

Algebra ->  Finance -> SOLUTION: 1. What's the one's digit of 2003^2004? A)9 B)7 C)3 D)1 2. The value of the 100-term sum 1/2+3/2+5/2+...+195/2+197/2+199/2 is A)5000 B)10,000 C)15,000 D)20,000      Log On


   

Question 1006288: 1. What's the one's digit of 2003^2004?
A)9
B)7
C)3
D)1
2. The value of the 100-term sum
1/2+3/2+5/2+...+195/2+197/2+199/2 is
A)5000
B)10,000
C)15,000
D)20,000
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
3,9,27,81,243,729...
it repeats after every fourth term.
Therefore, 2004 is a fourth term exponent, and the ones digit is 1.
D
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The middle of this series is 100/2, between the 50th term 99/2 and 51st 101/2
There are 100 terms, so 100/2*(100)=5000
A.