2018-09-28 06:56:34 -0600 received badge ● Famous Question (source) 2017-06-06 08:43:05 -0600 received badge ● Notable Question (source) 2016-11-05 16:51:12 -0600 received badge ● Popular Question (source) 2013-01-22 04:46:40 -0600 received badge ● Student (source) 2013-01-22 04:36:49 -0600 asked a question running sage from a Python script I'm using sage 5.5 on ubuntu 12.04. I'm trying to run sage via the following script #!/usr/bin/env sage -python import sys from sage.all import * sigma = 10 z = var('z') m0 = 128 P = exp(-(1/2)*z**2/sigma**2)/(sqrt(2*pi)*sigma) m = m0*exp(-(1/2)*z**2) mb = m0/sqrt(1+sigma**2) f = lambda u: 1-2*(numerical_integral(u*P*m**2/(mb*(u*mb+(1-u)*m)), 0, Infinity))[0] print find_root(f, 0.1, 1, rtol=0.01)  I run this from the command line with sage -python runDispK1.py and I get the following error Warning: invalid value encountered in absolute Warning: invalid value encountered in absolute Warning: invalid value encountered in absolute Warning: invalid value encountered in absolute Warning: invalid value encountered in absolute Traceback (most recent call last): File "runDispK1.py", line 16, in print find_root(f, 0.1, 1, rtol=0.01) File "/usr/lib/sagemath/local/lib/python2.7/site-packages/sage/numerical/optimize.py", line 108, in find_root raise RuntimeError, "f appears to have no zero on the interval" RuntimeError: f appears to have no zero on the interval  Whereas if I run the exact same code within sage, e.g. I have a file called run.sage with this text in it:  sigma = 10 z = var('z') m0 = 128 P = exp(-(1/2)*z**2/sigma**2)/(sqrt(2*pi)*sigma) m = m0*exp(-(1/2)*z**2) mb = m0/sqrt(1+sigma**2) f = lambda u: 1-2*(numerical_integral(u*P*m**2/(mb*(u*mb+(1-u)*m)), 0, Infinity))[0] print find_root(f, 0.1, 1, rtol=0.01)  then sage gives me the correct answer sage: load("run.sage") 0.550279773862  Is there something I'm missing here? I'm new to sage and python scripting but it seems the numerical_integral function is returning nothing useful, so I are these functions created incorrectly? Thanks