[Tex/LaTex] Can PSTricks or others draw the 4 common tangent lines of 2 “disjoint” circles without having to do extra calculations


There are two disjoint circles. Their centers and radii are given.
Without doing extra calculations, can we draw the 4 tangent lines using PSTricks (preferred) or others?

I asked many Illustrator, Free-hand, CAD experts, they cannot do it exactly. 🙂

Best Answer

pstricks-add knows a macro for calculating and saving 10 points as nodes, the two central points and the four points on each circle. See the documentation (run texdoc pstricks-add) for the names:

\usepackage{pstricks-add}% loads also pst-node



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