import geometry; size(10cm,0); // currentcoordsys=cartesiansystem((0,0),i=(1,0.5),j=(-0.5,.75)); show(currentcoordsys, xpen=invisible); point A=(-1,-1); point B=(0.75,0.5); dot("$A$",A,NW,red); dot("$B$",B,N,red); ellipse el1=ellipse(A,2,1.5); ellipse el2=ellipse(B,3,2); draw(el1); draw(el2,Arrow); point[] inter=intersectionpoints(el1,el2); dot("$M$", inter[0], 2NW, red); /**/ draw(tangents(el1,inter[0]), grey); draw(tangents(el2,inter[0]), grey); /**/ draw(tangent(el2,angabscissa(90)), grey);