gradient and Laplacian operator

例句：

1. 1.The gradient of the hill is steep.
   这座山的坡度很陡。
2. 2. The gradient of the road is changing.
   这条路的坡度在变化。
3. 3.The gradient of the river is important for navigation.
   河流的坡度对于航行很重要。
4. 1. In electromagnetic theory, the Laplacian operator is used to calculate the electric field.
   在电磁理论中，拉普拉斯算子用于计算电场。
5. 2. The Laplacian operator is a key tool in solving partial differential equations.
   拉普拉斯算子是解决偏微分方程的关键工具。
6. 3. The Laplacian operator is often used in image processing to enhance edges.
   拉普拉斯算子常用于图像处理，以增强边缘。