.. note:: :class: sphx-glr-download-link-note Click :ref:here  to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_showcase_integral.py: ================================== Integral as the area under a curve ================================== Although this is a simple example, it demonstrates some important tweaks: * A simple line plot with custom color and line width. * A shaded region created using a Polygon patch. * A text label with mathtext rendering. * figtext calls to label the x- and y-axes. * Use of axis spines to hide the top and right spines. * Custom tick placement and labels. .. image:: /gallery/showcase/images/sphx_glr_integral_001.png :class: sphx-glr-single-img .. code-block:: default import numpy as np import matplotlib.pyplot as plt from matplotlib.patches import Polygon def func(x): return (x - 3) * (x - 5) * (x - 7) + 85 a, b = 2, 9 # integral limits x = np.linspace(0, 10) y = func(x) fig, ax = plt.subplots() plt.plot(x, y, 'r', linewidth=2) plt.ylim(ymin=0) # Make the shaded region ix = np.linspace(a, b) iy = func(ix) verts = [(a, 0)] + list(zip(ix, iy)) + [(b, 0)] poly = Polygon(verts, facecolor='0.9', edgecolor='0.5') ax.add_patch(poly) plt.text(0.5 * (a + b), 30, r"$\int_a^b f(x)\mathrm{d}x$", horizontalalignment='center', fontsize=20) plt.figtext(0.9, 0.05, '$x$') plt.figtext(0.1, 0.9, '$y$') ax.spines['right'].set_visible(False) ax.spines['top'].set_visible(False) ax.xaxis.set_ticks_position('bottom') ax.set_xticks((a, b)) ax.set_xticklabels(('$a$', '$b$')) ax.set_yticks([]) plt.show() .. _sphx_glr_download_gallery_showcase_integral.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:Download Python source code: integral.py  .. container:: sphx-glr-download :download:Download Jupyter notebook: integral.ipynb  .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot Gallery generated by Sphinx-Gallery _