limit code doesn't compute some limits about sympy

[certik]

See also Rational.**pow**(), if we change it to raise pole_error on 0**0, then lot's
of limits fail. It doesn't have to be wrong behavior, but it smells.

Original comment: http://code.google.com/p/sympy/issues/detail?id=10#c1

Original author: https://code.google.com/u/104039945248245758823/

[certik]

**Labels:** Milestone-Release1.0  

Original comment: http://code.google.com/p/sympy/issues/detail?id=10#c2

Original author: https://code.google.com/u/104039945248245758823/

[certik]

Particularly, I know about these:

1) assert s.limitinf((3**x-5**x)**(1/x),x)==5

returns 1+log(5)

2) assert limit((sin(2_x)/x)_*(1+x),x,0) == 2

returns 1+log(2)

3) assert limitinf(sin(x)/x,x) == 0

returns 1

4) assert limit(x*sin(1/x),x,0) == 0

returns 1

1) and 2) are probably caused by the same problem, shouldn't be much difficult to
fix. 3) and 4) should either raise exception that it cannot calculate that, or do it
correctly.

Original comment: http://code.google.com/p/sympy/issues/detail?id=10#c3

Original author: https://code.google.com/u/104039945248245758823/

[certik]

I fixed 1) and 2)  (the correct form of 1 is of course 5**x-3**x)

The problem was in sympy.core, in the series expansion. I fixed it to work with these
two limits, but there is still a bug, see the issue 3127 .

Referenced issues: #3127

Original comment: http://code.google.com/p/sympy/issues/detail?id=10#c4

Original author: https://code.google.com/u/104039945248245758823/

[certik]

3) and 4) are fixed in the svn now. Closing the issue.

**Status:** Fixed  

Original comment: http://code.google.com/p/sympy/issues/detail?id=10#c5

Original author: https://code.google.com/u/104039945248245758823/