MathDB
Infinite Geometric Series

Source:

March 3, 2010
ratiogeometric series

Problem Statement

Let s s be the limiting sum of the geometric series 4\minus{} \frac83 \plus{} \frac{16}{9} \minus{} \dots, as the number of terms increases without bound. Then s s equals: <spanclass=latexbold>(A)</span> a number between 0 and 1<spanclass=latexbold>(B)</span> 2.4<spanclass=latexbold>(C)</span> 2.5<spanclass=latexbold>(D)</span> 3.6<spanclass=latexbold>(E)</span> 12 <span class='latex-bold'>(A)</span>\ \text{a number between 0 and 1} \qquad <span class='latex-bold'>(B)</span>\ 2.4 \qquad <span class='latex-bold'>(C)</span>\ 2.5 \qquad <span class='latex-bold'>(D)</span>\ 3.6 \qquad <span class='latex-bold'>(E)</span>\ 12