diff --git a/diushu.java b/diushu.java
new file mode 100644
index 0000000..2ac319a
--- /dev/null
+++ b/diushu.java
@@ -0,0 +1,9 @@
+package open;
+
+public class duishu {
+
+	public double duishu(double a,double b) {
+		return Math.log(a)/Math.log(a);
+	}
+
+}
\ No newline at end of file