So far all of tests for convergence have indicated whether or not a given series is absolutely convergent. As indicated earlier, some series converge but do not converge absolutely. If the terms in a series alternate between positive and negative values, the series is called an alternating series. Our final test gives us a simple criterion for determining the convergence of an alternating series. Using it will be able to show, for example, that the alternating harmonic series is conditionally convergent.