diff --git a/.obsidian/app.json b/.obsidian/app.json
index cf47506..d0aff95 100644
--- a/.obsidian/app.json
+++ b/.obsidian/app.json
@@ -1,7 +1,7 @@
 {
   "promptDelete": false,
   "newLinkFormat": "relative",
-  "attachmentFolderPath": "./assets/基础概念",
+  "attachmentFolderPath": "./assets/矩阵求导",
   "showUnsupportedFiles": false,
   "newFileLocation": "current",
   "useMarkdownLinks": true,
diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index 7f27a54..3fea0e2 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -13,7 +13,7 @@
             "state": {
               "type": "markdown",
               "state": {
-                "file": "Books/动手学深度学习/基础概念.md",
+                "file": "Study/DL/吴恩达深度学习课程/矩阵求导.md",
                 "mode": "source",
                 "source": false
               }
@@ -94,7 +94,7 @@
             "state": {
               "type": "backlink",
               "state": {
-                "file": "Books/动手学深度学习/基础概念.md",
+                "file": "Study/DL/吴恩达深度学习课程/矩阵求导.md",
                 "collapseAll": false,
                 "extraContext": false,
                 "sortOrder": "alphabetical",
@@ -111,7 +111,7 @@
             "state": {
               "type": "outgoing-link",
               "state": {
-                "file": "Books/动手学深度学习/基础概念.md",
+                "file": "Study/DL/吴恩达深度学习课程/矩阵求导.md",
                 "linksCollapsed": false,
                 "unlinkedCollapsed": true
               }
@@ -134,7 +134,7 @@
             "state": {
               "type": "outline",
               "state": {
-                "file": "Books/动手学深度学习/基础概念.md"
+                "file": "Study/DL/吴恩达深度学习课程/矩阵求导.md"
               }
             }
           },
@@ -167,8 +167,12 @@
   },
   "active": "82a60b2f86acd8d6",
   "lastOpenFiles": [
-    "Books/动手学深度学习/引言.md",
     "Books/动手学深度学习/基础概念.md",
+    "Study/DL/吴恩达深度学习课程/矩阵求导.md",
+    "Study/DL",
+    "Study",
+    "Study/DL/吴恩达深度学习课程",
+    "Books/动手学深度学习/引言.md",
     "Books/Java Guide/基础语法.md",
     "Books/Java并发编程/Java并发编程.md",
     "Books/从零开始深入学习Spring/IoC.md",
diff --git a/Study/DL/吴恩达深度学习课程/矩阵求导.md b/Study/DL/吴恩达深度学习课程/矩阵求导.md
new file mode 100644
index 0000000..1254017
--- /dev/null
+++ b/Study/DL/吴恩达深度学习课程/矩阵求导.md
@@ -0,0 +1,16 @@
+## 概念
+标量函数：输出为标量的函数
+$$
+f(x) = x^2
+$$
+向量函数：输出为向量/矩阵/张量的函数
+$$
+f(x) = 
+\left[ \begin{matrix}
+x & x^2 \\
+x^3 & x^4
+\end{matrix} \right]
+$$
+$$
+$$
+## 本质