The following source code shows how to plot two mathematical functions (one linear and one quadratic) using the Matplotlib library, save the result to a PNG image, and display it on the screen. The functions are:
This is the resulting image:
And the code:
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import matplotlib.pyplot as plt
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# Quadratic function.
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def f1(x):
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return 2*(x**2) + 5*x - 2
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# Linear function.
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def f2(x):
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return 4*x + 1
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# The X values to be plotted.
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x = range(-10, 15)
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# Plot both functions.
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# The second argument calculates the Y value for each of
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# the X values defined above.
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plt.plot(x, [f1(i) for i in x])
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plt.plot(x, [f2(i) for i in x])
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# Configure the color of the axes.
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plt.axhline(0, color="black")
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plt.axvline(0, color="black")
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# The range of values shown by each axis.
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plt.xlim(-10, 10)
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plt.ylim(-10, 10)
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# Save the plot as a PNG image.
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plt.savefig("output.png")
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# Show the result.
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plt.show()
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The Matplotlib library required by this code can be installed via python -m pip install matplotlib.