Insanely Different

evaluate

1) \sum_{n=1}^{\infty }\frac{1}{n^3(n+1)^3}

2) \sum_{n=1}^{\infty }\frac{1}{n^2(n+1)^2}

13 Answers

1
student ·

these sums that u r giving require higher calculus as they cannot be done using trivial methods like telescoping

1
Che ·

No brother ...why do u think so ;)

i wudnt hav given this if i wudnt hav seen this here in this thread

http://www.targetiit.com/iit-jee-forum/posts/practice-16277.html

post 18

if u can talk abt reimann zeta function here than u can very well solve this.

1
student ·

hmm ya may be MR.Ricky is well versed with the all these ,,

ok

i must have said "for iit aspirants "

its out of their range

1
Che ·

again i wud say u r overestimating the prob

it doesnt hav something so fancy.

1
" ____________ ·

2

\frac{\pi ^2}{3}- 3

ricky may haven infinte methods methods for dis

1
Che ·

ya tats teh ans

but more importantly u shud post ur soln.

1
Ricky ·

After telescoping ,

39
Pritish Chakraborty ·

I too was thinking of splitting by partial fractions...but can this be done without Riemann Zeta functions?

1
xYz ·

@ pritish

\zeta (2)=\sum_{n=1}^{\infty}{\frac{1}{n^2}}=\frac{\pi^2}{6}

take it as a fact

1
Ricky ·

1
Che ·

gr8 work genius.

1
Ricky ·

Well , this is directed to Nishant sir --

Nishant sir , once you asked , in the thread that asked to prove that the Harmonic series is divergent ( started by Subhomoy ) , that

summation of 1n 3 / 2 uptil infinity is convergent or divergent ?

But for any P - series , I mean , any zeta function having exponent greater than 1 has to converge to a finite value , shouldn't it ?? So the series is convergent .

62
Lokesh Verma ·

yes you are right.. but then we were trying to prove that by some rule... which rule wud you use here?

Your Answer

Close [X]