Problem with matplotlib's rcParams['figure.figsize'] in the notebook

[boffi]

If I change the size of a figure in the cell where I have %matplotlib ... the change is not effective.

%matplotlib inline
import matplotlib.pyplot as plt
plt.rc('figure', figsize=(10,2))
plt.plot((0,1), (1,0));

Please see (after renaming the file) a minimal example of my problem in the attached notebook.

example_ipynb.txt

[rileypeterson]

Duplicate of #3385