Question 842311:  What are multiples of 1/5 and how do you write the multiples as a sum 
 Answer by richwmiller(17219)      (Show Source): 
You can  put this solution on YOUR website! Curiously even though we are talking about multiples of 1/5 it will be  an arithmetic sequence not geometric. 
1/5, 2/5, 3/5,4/5
 
 
First term is 1/5 and the difference is 1/5 
S = ½(2a + (n-1)d)n 
positive S = ½(2/5 + (n-1)/5)n 
negative S = ½(-2/5  -(n-1)/5)n 
If we also include negative multiples of 1/5  
First term is -1/5 and the difference is -1/5 
then the sum will be zero because the pluses and minuses add up to zero.
 
S = ½(2/5 + (n-1)/5)n+ ½(-2/5  -(n-1)/5)n=0 
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