Sequence And Series Question 126
Question: If $ \sum\limits_{i=1}^{n}{i=\frac{n(n+1)}{2}} $ , then $ \sum\limits_{i=1}^{n}{(3i-2)=} $
Options:
A) $ \frac{n(3n-1)}{2} $
B) $ \frac{n(3n+1)}{2} $
C) $ n(3n+2) $
D) $ \frac{n(3n+1)}{4} $
Show Answer
Answer:
Correct Answer: A
Solution:
$ \sum\limits_{i=1}^{n}{{}}=3\sum\limits_{i=1}^{n}{i}-2\sum\limits_{i=1}^{n}{1}=3\frac{n,(n+1)}{2}-2n=\frac{n,(3n-1)}{2} $ .
BETA
