Add Geometric Mean Task

src/main/java/task/TaskGeometricMean.java

+package task;
+
+import java.util.Arrays;
+
+public class TaskGeometricMean extends TaskImpl {
+
+    @Override
+    public void execute() {
+        String[] stringArray = input.split(",");
+        double[] doubleArray = Arrays.stream(stringArray)
+                .mapToDouble(Double::parseDouble)
+                .toArray();
+
+        // Calculate the geometric mean
+        double product = Arrays.stream(doubleArray).reduce(1.0, (a, b) -> a * b);
+        double geometricMean = Math.pow(product, 1.0 / doubleArray.length);
+        result = String.valueOf(geometricMean);
+    }
+}