Sum of geometric sequence
for the sum where the initial value is a₁ and the common ratio is r and the term is n
common ratio is -3
-5 times -3 is 15, -15 times -3=-45 etc
first term is -5
and we want the 8th term
the sum is 8200
for the sum where the initial value is a₁ and the common ratio is r and the term is n
common ratio is -3
-5 times -3 is 15, -15 times -3=-45 etc
first term is -5
and we want the 8th term
the sum is 8200