bug in simple limit

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list...@gmail.com

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Feb 14, 2019, 4:37:21 PM2/14/19
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Hello.

I have found the following bug in limit.

┌────────────────────────────────────────────────────────────────────┐

│ SageMath version 8.6, Release Date: 2019-01-15                    

│ Using Python 2.7.15. Type "help()" for help.                      

└────────────────────────────────────────────────────────────────────┘

sage: f=exp(-2*x^2)-cos(2*x);f

-cos(2*x) + e^(-2*x^2)

sage: g=x*(sin(x))^3;g

x*sin(x)^3

sage: lim(f/g,x=0) # this is wrong

und

sage: lim(f/g,x=0,dir='-'),lim(f/g,x=0,dir='+') # the second result is wrong

(4/3, +Infinity)

sage: taylor(f/g,x,0,3) # this is right

-26/45*x^2 + 4/3

sage: lim(f/x^4,x=0) # this is right too

4/3

sage: 


Any ideas?  Thanks in advance.

Guillermo

Emmanuel Charpentier

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Feb 17, 2019, 6:28:47 AM2/17/19
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You are right. Did you file a ticket ?

list...@gmail.com

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Feb 17, 2019, 11:16:42 AM2/17/19
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This is now https://trac.sagemath.org/ticket/27311

(this is my first ticket, I hope everything is OK).
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