diff --git a/README.md b/README.md
index 7b85b0c..363e5d0 100644
--- a/README.md
+++ b/README.md
@@ -393,6 +393,14 @@ $date = Jalalian::now()->lessThanOrEqualsToCarbon(Carbon::now()))
 
 ```
 
+---
+```php
+public function getFirstDayOfWeek(): bool
+
+$date = (new Jalalian(1403, 10, 14))->getFirstDayOfWeek()
+// output: 1403, 10, 8
+
+```
 ---
 ```php
 public function isStartOfWeek(): bool