Question

Find the indicated sum for each sequence. S9 of –9, 36, –144, 576, ...

Answer 1

This is a geometric sequence with a common ratio of -4:

-9*-4=36

36*-4=-144

-144*-4=576

Thus, the 9th term would be equal to:

(-4)^5*576 which is -589824

The exponent 5 comes from the fact that 4 terms have already been displayed and we need 9-4 more terms to get to the 9th term. Since we are multiplying by -4 only, the 5 remains an exponent