Question

Find the sum of the series using the formula

s=a1/(1-r)



27 + 9 + 3 + 1 + ...

Answer 1

We have a1 = 27 and r = 3 (because 27:9 = 3; 9:3 = 3; 3:3 = 1);

Then s = 27 / (1 - 3) ;

Finally, s = - 27 / 2;

Explanation: