[newton_method] Execution issue / Translation

The following error is being reported


```bash
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[19], line 1
----> 1 k_star_近似牛顿法

NameError: name 'k_star_近似牛顿法' is not defined
```

@HumphreyYang it looks like the AI has transferred some of the code variable name to Chinese. 