## anonymous one year ago Find S12 for the series 1 + 1.5 + 2.25 + 3.375 +...

1. ParthKohli

A geometric series with common ratio 3/2.

2. anonymous

I got 86.49 as the 12 number in the series. Is that correct?

3. triciaal

verify that the question is not asking for the 12th term it is asking for the sum of the first 12 terms.

4. ParthKohli

Yes, but if you have to find the sum, you use$S (n) = a\times\dfrac{ r^n-1 }{r -1}$

5. anonymous

okay, I was just wondering if the number that I got for the 12th term was correct.

6. triciaal

so you wanted T12 ok T12 = ar^n-1 a= 1, n = 12, r = 3/2 T12 = (1)(3/2)^(12-1) = (3/2)^11 =

7. anonymous

I got 258.49 as my over all answer, Is this correct?

8. anonymous

IS 258.49 correct for the sum of the terms

9. triciaal

|dw:1433909448209:dw|

10. anonymous

when I did that I got 257.49?

11. triciaal

|dw:1433909575762:dw|