projecteuler.net

An Arithmetic Geometric sequence

Problem 235

Published on 07 March 2009 at 05:00 am [Server Time]

Given is the arithmetic-geometric sequence u(k) = (900-3k)rk-1.
Let s(n) = Σk=1...nu(k).

Find the value of r for which s(5000) = -600,000,000,000.

Give your answer rounded to 12 places behind the decimal point.


Answer:
Confirmation Code:
Go to back to Problems