SOLUTION: Find the value of the series 11+13+15+...+61.

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Question 911236: Find the value of the series 11+13+15+...+61.
Found 2 solutions by Fombitz, MathLover1:
Answer by Fombitz(32388) About Me  (Show Source):
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
11%2B13%2B15%2B...%2B61
formula:a%5Bn%5D=%282n%2B9%29

a%5Bn%5D=%282n%2B9%29 => a%5B1%5D=%282%2A1%2B9%29=11
a%5Bn%5D=%282n%2B9%29 => a%5B2%5D=%282%2A2%2B9%29=13
:
:
if 2%2An%2B9=61 => 2%2An=61-9=> 2%2An=52=> n=26; so, there are 26 terms in this sequence and
sum%28+%282n%2B9%29%2C+n=1%2C+26+%29=+936