# Place a point on a conic at a given parameter value

Peter Liepa shared this question 2 years ago

Given an ellipse c, I can place a point A on it and retrieve the parameter value with PathParameter(A). Can I go in the other direction, i.e. place a point B on c at the position corresponding to a parameter t?

Assume the ellipse c was constructed via one of the usual commands, e.g. by specifying 2 foci and a point. Geogebra maintains a parametric version of this ellipse, which is why the PathParameter command works here. I can retrieve the implicit equation for the ellipse using the Coefficients command, but I don't see how to retrieve information about the parametric equation, or how to use it indirectly to place a point.

The reason I'm asking is that I'd like to place a series of tangents or points on the ellipse c corresponding to equally spaced parameter values.

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Just an idea to get equally spaced points on an ellipse.

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It uses the syntax

Point( <Object>, <Parameter> ) Returns a point on the geometric object with given path parameter.

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Thanks, that's exactly what I need.