The sum of a certain infinite geometric series is 2. The sum of the squares of all the terms is 4. Find the common ratio.
Are you the person that has posted this question 3 - 4 times ?? We told you under your your fiirst post that the sum of the squares CANNOT be 4 !! Why? Because:
2 ==F / [1 - R].................(1)
4 ==F^2 / [1 - R^2]........(2), solve for F, R
F ==2 - this is the first term
R==0 - this is the common ratio.
So: what does the above mean? It means that your infinte series has ONLY 1 term!!!!!. Which is 2, because the sum of the first term==2 and 2^2 ==4 !!!. Therefore, your question does not make sense the way it is written. The 4 in your question should be 3. Wherever you got it from, bring it to the attention of your Math Teacher.