Question 864137: What is the sum of the first 10 terms of the sequence defined by an=3n-3?
Found 2 solutions by stanbon, richwmiller:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! What is the sum of the first 10 terms of the sequence defined by an=3n-3?
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a(1) = 3-3 = 0
a(2) = 3*2-3 = 3
a(3) = 3*3-3 = 6
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a(10) = 3*10-3 = 27
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Sum of 1st 10::
S(10) = (10/2)(0+27) = 5*27 = 135
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Cheers,
Stan H.
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Answer by richwmiller(17219)  (Show Source):
You can put this solution on YOUR website! an=3n-3=3*(n-1)
a1=3-3=0
a2=3*2-3=3
a3=3*3-3=6
a4=3*4-3=9
a5=3*5-3=12
a6=3*6-3=15
a7=3*7-3=18
a8=3*8-3=21
a9=3*9-3=24
a10=3*10-3=27
0,3,6,9,12,15,18,21,24,27=135
S = ½(2a + (n-1)d)n
S = ½(2*0 + (9)3)10=135
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