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
index 819937f..0a34dce 100644
--- 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
@@ -27,6 +27,10 @@ $\frac{dB}{dA} = \frac{d(f(A))}{dA}$ 即 `B` 对 `A` 中的每个变量进行求
    $$
 	\frac{d(U^T V)}{dX} = \frac{\partial{U}}{\partial{X}} V + \frac{\partial{V}}{\partial{X}} U
     $$
+2. 加法
+   $$
+	\frac{d(U+V)}{dX} = \frac{dU}{dX} + \frac{dV}{dX}
+    $$
 ## 常见公式推导
 1. 
 	$$\begin{aligned}