下边代码会画出一个y=cos(x)的图像：

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(-2,2,100)
y=np.cos(np.pi*x)

plt.plot(x,y,'go')
plt.title(r"$y=\cos(\pi | time x$")
plt.show()

在Jupyter lab运行的时候，发现报错如下：

ModuleNotFoundError: No module named 'matplotlib'

conda install matplotlib -c https://mirrors.bfsu.edu.cn/anaconda/pkgs/main/ -n jupyterlabuse从清华python源里边安装matplotlib。

完成之后显示：

Preparing transaction: done
Verifying transaction: done
Executing transaction: done

Note: you may need to restart the kernel to use updated packages.

运行结果如下图：