Is their a formula for finding the Sum for Geometric Series?

http://en.wikipedia.org/wiki/Geometric_series

The sum of the first two term of a G.P is 8/9 of the sum to infinity. Find the common ratio.

Yes, there is a formula for finding the sum of a geometric series. The formula is as follows:

S = a(1 - r^n) / (1 - r),

where:
- S is the sum of the series,
- a is the first term of the series,
- r is the common ratio,
- n is the number of terms in the series.

To use this formula, you need to know the values of a, r, and n.

Here's how you can find the sum of a geometric series using the formula:

1. Identify the values of a, r, and n in the given series.
2. Plug these values into the formula for the sum of a geometric series.
3. Simplify the expression and calculate the final result.

Note that the formula only works if the value of the common ratio (r) is not equal to 1. If r equals 1, the series is not a geometric series, and the sum will be infinite.