% 1. Definition of characteristic points \figinit{in} % Data \figpt 0:$O$(-0.5,0)\figpt 1:$C$(2,0) \def\Rx{1}\def\Ry{0.7} % Computations \figptbary2:$A$[0,1;1,1]\figgetdist\RHO[2,1] \figptsintercirc 3[1,\Rx;2,\RHO] % Computes points 3 (I') and 4 (J') \figptbary 10:[0,1;6,-1]\figptbaryR 11:$B$[0,1;-1,2.5] \figgetangle\ThetaI[1,11,3] \figgetangle\ThetaJ[1,11,4] \figptell 3:$I$: 1;\Rx,\Ry (\ThetaI,0) \figptell 4:$J$: 1;\Rx,\Ry (\ThetaJ,0) \figptbary 13:[0,3;-1,3] \figptbary 14:[0,4;-1,3] % 2. Creation of the graphical file \psbeginfig{} \psarcell 1;\Rx,\Ry (0,360,0) \psline[10,11]\psline[0,13]\psline[0,14] \psendfig % 3. Writing text on the figure \def\dist{4pt} \figvisu{\figBoxA}{\bf Tangent lines to the ellipse passing through $O$}{ \figwriten 0:(\dist)\figwriten 11:(\dist) \figsetmark{+}\figwriten 2:(\dist) \figsetmark{$\figBullet$}\figwriten 1:(\dist) \figsetmark{$\times$}\figwriten 3,4:(\dist) } \centerline{\box\figBoxA}