Hi Michael, >If you mean construct a line tangent to a circle given a point on the line that is not on the circle, then no >there isn't because that gives multiple solutions Yes I know.. but intersecting a line with a circle give multiple solution too ..
In case of a point out of a circle we get 2 tangent Line and it’s easy to calculate .. If you get the Polar Line referred at the circle p:xX+yY+a(X+x)/2+b(Y+y)/2+c=0 Where (x,y) are the external point and x^2+y^2+ax+by+c=0 is the circle equation. Intersect the Polarline with the circle and you get the intersection points.. There is any easy way to compute this with sympy? Regards, Matteo From: [email protected] [mailto:[email protected]] On Behalf Of Michael Hoffman Sent: 28 May 2010 19:27 To: [email protected] Subject: Re: [sympy] Pythoncad & sympy.geometry Mathematically I don't think so, but I may be misunderstanding you. If you mean construct a line tangent to a circle given a point on the line that is not on the circle, then no there isn't because that gives multiple solutions. For example, take any two tangent lines with different slopes. In 2-d space these lines will intersect and hence give a point and a circle that corresponds to at least two tangent lines. Or even easier inscribe a circle in a square. Any two perpendicular lines on the square intersect at a vertex of the square and the two perpendicular lines both correspond to a point (the vertex) and a circle. Mike On Fri, May 28, 2010 at 7:13 AM, Matteo Boscolo <[email protected]> wrote: Hi all, I'm New using in sympy I would like to use sympy.geometry for my pythoncad Application. There are any way to find a tangent line of a circle or ellipse given as constraint an external point ?.. somthing like Line=TangentLine(Circle,Point) where point is an external entity of the circle ? I found the Circle.tangent_line(Point) .. but this means that i have to know the tangent point .. There are simple way to do such a operation ? Regards Matteo -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en. -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en. -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
