Saturday, November 16, 2013

Find the sum of the arithmetic sequence: 16+22+28+ ... +112

a%5B1%5D=16
a%5Bn%5D=112
d=22-16=6

a%5Bn%5D=a%5B1%5D%2B%28n-1%29d

112=16%2B%28n-1%29%2A6
n=%28112-16%29%2F6%2B1=17


S%5Bn%5D=%28n%2F2%29%28a%5B1%5D%2Ba%5Bn%5D%29

S%5Bn%5D=%2817%2F2%29%2816%2B112%29=1088 
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