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GeoGebra - bug report

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Dear Ladies and Gentlemen!

I have discovered two problems with the GeoGebra-command Tangent:

1. By chance I acchieved to construct a tangent from a point which  
does NOT lie on the curve, but the parameter-options for the command  
Tangent
only contain Tangent[Point on Curve, Curve]        (1)
not Tangent[point, curve]!                        (2)

2. While Tangent works for purpose (2), it does not work for purpose  
(1) - for implicit curves at least:

I have considered an implicit curve (algebraic curve, order 3), a  
point P in the plane and the tangent from P to c.

A = 1        B = 1        P=(-2,1)                c: A x³ + B y = 0     
     t = Tangent[P,c]

I see 4 tangents to c through P, but if I change P to (0,0), save the  
file,reopen it, two windows appear saying: 'opening file failed'  and  
a new ggb-window is opened but  I cannot open the saved file!

Of course it would be easy to solve this problem defining explicitely  
f(x) = -x^3 instead of c,
but I am interested in tangents in given points of any algebraic curve  
which cannot be defined explicitely!

Best wishes and thanks for clearing this problem!

Walter Lenzenweger

P.S. I am using a Dell-notebook XPS L502X, Windows 7

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GeoGebra - bug report Walter Lenzenweger <Walter.Lenzenweger@student.uibk.ac.at> - 2015-08-23 02:40 +0200
  Re: GeoGebra - bug report Geert Stappers <stappers@stappers.it> - 2015-08-24 17:30 +0200
  Re: GeoGebra - bug report Emmanuel Bourg <ebourg@apache.org> - 2015-08-25 01:00 +0200

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