Update examples in array-update documentation

Author: abinav2307

articles/cosmos-db/mongodb/vcore/operators/array-update/$.md

@@ -72,7 +72,57 @@ Consider this sample document from the stores collection.
 }
 ```
 
-### Example 1: Update discount percentage for a specific category
+### Example 1: Project the first element of an array, matching the condition
+
+This query returns the first element within the `salesByCategory` array, for `DJ` equipment with `totalSales` greater than 35000.
+
+```javascript
+db.stores.find({
+    "sales.salesByCategory": {
+        $elemMatch: {
+            "categoryName": {
+                $regex: "^DJ"
+            }
+        }
+    },
+    "sales.salesByCategory.totalSales": {
+        $gt: 35000
+    }
+}, {
+    "sales.salesByCategory.$": 1
+}).limit(2)
+```
+
+The first two results returned by this query are:
+
+```json
+[
+  {
+    "_id": "d3c9df51-41bd-4b4e-a26b-b038d9cf8b45",
+    "sales": {
+      "salesByCategory": [
+        {
+          "categoryName": "DJ Speakers",
+          "totalSales": 36972
+        }
+      ]
+    }
+  },
+  {
+    "_id": "7954bd5c-9ac2-4c10-bb7a-2b79bd0963c5",
+    "sales": {
+      "salesByCategory": [
+        {
+          "categoryName": "DJ Headphones",
+          "totalSales": 35911
+        }
+      ]
+    }
+  }
+]
+```
+
+### Example 2: Update discount percentage for a specific category
 
 The example updates the discount percentage for "Desks" category in the first matching promotion event.
 
@@ -91,7 +141,7 @@ db.stores.updateOne(
 )
 ```
 
-### Example 2: Update sales category total
+### Example 3: Update sales category total
 
 The example updates the total sales for a specific category using the `$ (positional operator)`.