# Thread: Question on series,pls help to check

1. ## Question on series,pls help to check

hi everyone

need help to verify my working.
question:
compute S5 for
an(limit=infinity,n=1) if 1/(n(n+1))

my working=
n=1,= 1/(1(1+1)) =1/2
n=2,= 1/(2(2+1)) =1/6
n=3,= 1/(3(3+1)) =1/12
n=4,= 1/(4(4+1)) =1/20
n=5,= 1/(5(5+1)) =1/30

sum = 1/2+1/6+1/12+1/20+1/30 = 5/6

2. Is this about a sum of fractions? Well, uh... Yes, 1/2+1/6+1/12+1/20+1/30 = 5/6.

3. He was only asking for a check. The question, as I finally realized, was to find the fifth partial sum.

4. hi everyone.

question
$\displaystyle \sum_{n=1}^{infinity} a_n$ if $\displaystyle a_n$=1/(n(n+1)).

5. Originally Posted by anderson
thank you for all your response.. did i do it right?]

how do i insert sigma notation, can someone help me

Are you familiar with latex?

{math}\sum_{p}^{q}a_p{/math}

Will result in:

$\displaystyle \sum_{p}^{q}a_p$

6. You also posted this under "Calculus" as "Series sum question, is this correct?" Please do NOT double post!

7. no,that is a different question, please look again. but it all involves $\displaystyle S_5$.