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Mathematics 7 Online
OpenStudy (anonymous):

Hi can someone help me find a formula for the nth term of telescoping series?? Then need to find limit. Equation enclosed.

OpenStudy (anonymous):

\[\sum_{1}^{\infty} (1/(k+1)) - (1/(k+2))\]

OpenStudy (amistre64):

if its telesoping, then certain pairs cancel out

OpenStudy (amistre64):

write out a few terms if need be

OpenStudy (anonymous):

Yes so I will be left with first and last terms I believe. should be 1/2 - 1/k+2

OpenStudy (amistre64):

seems about right

OpenStudy (amistre64):

1/infinity = 0 doesnt it?

OpenStudy (amistre64):

or rather it limits itslef to zero

OpenStudy (anonymous):

my book shows this and then says it is equal to k/2k+4

OpenStudy (anonymous):

which is th epart I am having trouble understanding. I took my limit with 1/2 - 1/k+2 which equals 1/2

OpenStudy (anonymous):

Bu tI dont undertstand how they come up with the generic formula which was supposed to be in terms of n ......n/2n+4

OpenStudy (amistre64):

1 1 - - ----- 2 k+2 (k+2) 2 ----- - ----- 2(k+2) 2(k+2) k ----- 2k+4

OpenStudy (anonymous):

ahhhh thanks (;

OpenStudy (amistre64):

just add the fractions

OpenStudy (amistre64):

since the top and bottom are of the same degree ... it limits to 1/2 as well

OpenStudy (amistre64):

but that could be seen simply from the first setup. 1 1 - - ----- 2 k+2 ^^^^^^ this term limits to zero leaving us with 1/2

OpenStudy (anonymous):

right.....so this is a good formula for the nth term but I like the other version better with first and last term to find the limit ........

OpenStudy (anonymous):

exactly...

OpenStudy (anonymous):

thank you

OpenStudy (amistre64):

youre welcome :)

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