How do you find the sum of the infinite geometric series 1-(1/3) + (1/9) - (1/27) + .....?

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Answer 1 · 2016-02-22T01:01:25

The formula for sum of an infinite geometric series is #s_oo = a/(1 - r)#

We must first find the common ratio, r, which can be found by using the formula #r = t_2/t_1#

#r = (-1/3)/1#

#r = -1/3#

a is the first term, 1.

#s_oo = 1/(1 - (-1/3))#

#s_oo = 1/(4/3)#

#s_oo = 3/4#

The sum is #3/4#.

Hopefully this helps!