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coolaidd
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pretty sure you have to use the partial sums formula for 8
do u know formulae for sum of finite and infinite terms in a geometric sequence??
It's a geometric series a + ar + ar^2 + ... with a=1 and r = 3/2. Plug into the formula
http://en.wikipedia.org/wiki/Geometric_progression if u have finite geometric progession the sum is a1(q^n-1)/(q-1) if u have infinite geometric progresion the formula is a1/(1-r) where where a1 is the first therm r is the common ratio (u multyply all therms in progresion )