Re: C2 Geometric series help

Quote:

Originally Posted by

**DonGorgon** Stuck here on the sufficient method to approach this question, would it involve using the a(1-r^n)/1-r formula? Any assistance would be greatly appreciated.

'The sum of the first four terms of a geometric series is 5468.75 and the first term is 2000. Find the value of the common ratio and if all the terms are positive.'

You have all the parts, use them.

$\displaystyle 5468.75=\frac{2000(1-r^4)}{1-r}$

Re: C2 Geometric series help

2000r^4 - 5468.75r 3468.75 = 0

Along the right lines?