How to plot a function using matplotlib

We will see how to evaluate a function using numpy and how to plot the result.

import pylab
import numpy

x = numpy.linspace(-15,15,100) # 100 linearly spaced numbers
y = numpy.sin(x)/x # computing the values of sin(x)/x

# compose plot
pylab.plot(x,y) # sin(x)/x
pylab.plot(x,y,'co') # same function with cyan dots
pylab.plot(x,2*y,x,3*y) # 2*sin(x)/x and 3*sin(x)/x
pylab.show() # show the plot

The command pylab.show() will open a window with the following plot: