Question 1086471:  Determine the general term for the following sequence: 1, -3, 9, -27.  I came up with -3^n-1, which was marked wrong.  Any insight would be much appreciated... 
 Found 2 solutions by  Boreal, MathTherapy: Answer by Boreal(15235)      (Show Source): 
You can  put this solution on YOUR website! With these, make (-1)^(n) the sign changer then 3^n.  That way, one can make the index n=0 to whatever value is desired.  
-1^0*3^0 
-1^1*3^1 
-1^2*3^2 
-1^3*3^3 
 Answer by MathTherapy(10557)      (Show Source): 
You can  put this solution on YOUR website!  
Determine the general term for the following sequence: 1, -3, 9, -27.  I came up with -3^n-1, which was marked wrong.  Any insight would be much appreciated... 
   
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