If you are running 32-bit 3.6 on Windows, please test this

[Terry Reedy]

https://stackoverflow.com/questions/45965545/math-sqrt-domain-error-when-square-rooting-a-positive-number

reports the following:
-----
Microsoft Windows [Version 10.0.16251.1002]
(c) 2017 Microsoft Corporation. All rights reserved.

C:\Users\Adam>python
Python 3.6.2 (v3.6.2:5fd33b5, Jul  8 2017, 04:14:34) [MSC v.1900 32 bit 
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
 >>> import math
 >>> math.sqrt(1.3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: math domain error
 >>>

I upgraded from version 3.6.1 to 3.6.2 to try to resolve the issue and 
restarted my computer but it is still occurring. Some numbers are 
working (1.2, 1.4) and some others are also not working (1.128).
----

Neither installed 64 bit 3.6.2 nor my repository 3.6 32-bit debug build 
reproduce this.  If anyone has the python.org 32bit 3.6.1/2 releases 
installed on Windows, please test and report.

-- 
Terry Jan Reedy