--- 
+++ 
@@ -22,7 +22,7 @@
         } while ((fa * fb > 0.0) && (numIterations < maximumIterations) && 
                 ((a > lowerBound) || (b < upperBound)));
    
-        if (fa * fb >= 0.0 ) {
+        if (fa * fb > 0.0) {
             throw new ConvergenceException(
                       "number of iterations={0}, maximum iterations={1}, " +
                       "initial={2}, lower bound={3}, upper bound={4}, final a value={5}, " +