|   | 1 |  initial version  | 
Not sure if/when the default rtol was changed, but my colleague just showed me how to overwrite it for a whole notebook:
from functools import partial
find_root = partial(find_root, rtol=1e-9)
 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
 
                
                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.