Dear Math Teacher;

I work in Rock Mechanics and we have a standard methodology of description of State of Stress called Mohr Circle... It is basically a series of circles with their centers lying on the X axis and having various radius. A rock Mechanics Parameter called MOHR ENVELOP is a curve (most probably a Hyperbola) that is tangent to all those circles... 'm trying to find th equations of such a Hyperbola that would TANGENT to such several circles... any clue? (I was able to extract and apply (on Mathematica) the equation of a line that is tangent to two circles)

Thank you

Yasser