clearly the common ratio is -7/6, so the series S diverges.
However, assuming r = -6/7,
a/(1-r) = a/(1+6/7) = a/(13/7) = 7/13 a = 1085/13
so, a = 1085/13 * 13/7 = 1085/7 = 155
S = 631 - 4417/6 + 30919/36 - 216433/216 ...
A different geometric sequence has r = -6/7 and the first term is denoted x. Is this series convergent or divergent? If it is convergent, what value of x yields an infinite sum of 1085/13?
1 answer