Evaluate the summation of 3 n plus 2, from n equals 1 to 14..
\[\sum_{n=1}^{14} 3n + 2\]
Answer options A) 39 B) 49 C) 340 D) 343
Well first we can break it up using properties of summation \[\sum_{i}^{n} (c + ai) = \sum_{i = 1}^{n}c + \sum_{i=1}^{n}ai\] So here, we would have \[\sum_{n=1}^{14} 3n + \sum_{n=1}^{14} 2\] Using the properties of summation we know that \[\sum_{i}^{n}c = cn\] and \[\sum_{i}^{n}i = \frac{n(n + 1)}{2}\] So lets rewrite yours as \[3\sum_{n=1}^{14} n + \sum_{n=1}^{14} 2\] Which would be \[\large 3\frac{14(15)}{2} + 2(14)\] What does that come out to?
\[\sum_{n=1}^{14}3n+2=\sum_{n=1}^{14}3n+\sum_{n=1}^{14}2=3\sum_{n=1}^{14}n+\sum_{n=1}^{14}2\] remember the rule \[\sum_{i=1}^{n}i=\frac{n(n+1)}{2}\]
id I tried to answer it but a reaaaaaaaaally long number came up @johnweldon1993
do the algebra that john listed at the end and you should find a useful answer
the number is long
We have \[\large \frac{3\times 14\times 15}{2} + 2(14)\]
So 3*14*15 = 630 That divided by 2 = 315 And 315 + 2(14) 2 times 14 = 28 315 + 28 = ?
3433
...assuming you accidentally put an additional 3 at the end...
yeah sorry lol
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