# Copyright (C) 2020 Andreas Kloeckner # #

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# In this notebook, we'll investigate two common sources of error: Truncation error and rounding error.
# In[1]:
import numpy as np
import matplotlib.pyplot as pt
# **Task:** Approximate a function (here: a parabola, by a line)
# In[15]:
center = -1
width = 6
def f(x):
return - x**2 + 3*x
def df(x):
return -2*x + 3
grid = np.linspace(center-width/2, center+width/2, 100)
fx = f(grid)
pt.plot(grid, fx)
pt.plot(grid, f(center) + df(center) * (grid-center))
pt.xlim([grid[0], grid[-1]])
pt.ylim([np.min(fx), np.max(fx)])
# * What's the error we see?
# * What if we make `width` smaller?
# In[ ]: