Question

Evaluate:

lim x->infinity \[(5/n^3)(n(n+1)(2n+1) / 6)\]

Answer 1

10/6

Answer 2

man, try www.wolframalpha.com

Answer 3

Sorry the brackets may be confusing its 5/n^3 times the other function over 6

Answer 4

As n becomes large you can ignore the 1 in n+1 and 2n+1 . This gives you a n^3 term to cancel the bottom n^3 giving you 10/6

Answer 5

Oh i see, though the answer is 5/6

Answer 6

http://www.wolframalpha.com/input/?i=lim+n-%3Einfinity+%5B%285%2Fn%5E3%29%28n*%28n%2B1%29*%282n%2B1%29%2F6%29%5D

Answer 7

Thanks for the link

Answer 8

I think the answer should be 10/6 because the 2 does not disappear in 2n+1. This 2 is multiplied by the 5 in the other expression to give 10/6. Or am I missing something?