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59 lines
1.5 KiB
Markdown
59 lines
1.5 KiB
Markdown
# 积分作为曲线下面积
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虽然这是一个简单的例子，但它展示了一些重要的调整：
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- 带有自定义颜色和线宽的简单线条图。
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- 使用Polygon补丁创建的阴影区域。
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- 带有mathtext渲染的文本标签。
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- figtext调用标记x轴和y轴。
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- 使用轴刺来隐藏顶部和右侧脊柱。
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- 自定义刻度线和标签。
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```python
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import numpy as np
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import matplotlib.pyplot as plt
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from matplotlib.patches import Polygon
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def func(x):
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return (x - 3) * (x - 5) * (x - 7) + 85
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a, b = 2, 9 # integral limits
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x = np.linspace(0, 10)
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y = func(x)
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fig, ax = plt.subplots()
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plt.plot(x, y, 'r', linewidth=2)
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plt.ylim(ymin=0)
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# Make the shaded region
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ix = np.linspace(a, b)
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iy = func(ix)
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verts = [(a, 0), *zip(ix, iy), (b, 0)]
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poly = Polygon(verts, facecolor='0.9', edgecolor='0.5')
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ax.add_patch(poly)
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plt.text(0.5 * (a + b), 30, r"$\int_a^b f(x)\mathrm{d}x$",
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horizontalalignment='center', fontsize=20)
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plt.figtext(0.9, 0.05, '$x$')
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plt.figtext(0.1, 0.9, '$y$')
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ax.spines['right'].set_visible(False)
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ax.spines['top'].set_visible(False)
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ax.xaxis.set_ticks_position('bottom')
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ax.set_xticks((a, b))
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ax.set_xticklabels(('$a$', '$b$'))
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ax.set_yticks([])
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plt.show()
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```
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## 下载这个示例
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- [下载python源码: integral.py](https://matplotlib.org/_downloads/integral.py)
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- [下载Jupyter notebook: integral.ipynb](https://matplotlib.org/_downloads/integral.ipynb) |