Tashalee student The sum of the first 3 terms of a geometric series is 13. The sum of their reciprocal is 13/9. how do you find the first three terms? Hi Tashalee,
Since you have a geometric series the first three terms can be written for some numbers a and r. Thus you have and or Multiplying the numerator and denominator br a gives Since a^{2}r^{2} = 9 and thus ar = 3 or a = ^{3}/_{r}. Substitute into the above equation and solve for r. Cheers, Penny
