Saturday, 22 February 2014

`8+6+9/2+27/8+...` Find the sum of the convergent series.

`8+6+9/2+27/8+........`


Let's find the common ratio of the terms:


`r=a_2/a_1=6/8=3/4`


`r=a_3/a_2=(9/2)/6=9/12=3/4`


So this is a geometric sequence with common ratio of `3/4`


`S_oo=a/(1-r)`  where a is the first term


`S=8/(1-3/4)`


`S=8/(1/4)`


`S=32`


The sum of the given convergent series is 32.

`8+6+9/2+27/8+........`


Let's find the common ratio of the terms:


`r=a_2/a_1=6/8=3/4`


`r=a_3/a_2=(9/2)/6=9/12=3/4`


So this is a geometric sequence with common ratio of `3/4`


`S_oo=a/(1-r)`  where a is the first term


`S=8/(1-3/4)`


`S=8/(1/4)`


`S=32`


The sum of the given convergent series is 32.

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