// tangent-parabola2.ggb 4s, 2.8s, 2.47s, 1.65s, 1.45s, 1.38s, 1.33s, 1.17s, 1.03s
//[v6^2*v5*v4^2*v3^2+v5^3*v4^2*v3^2+v6^3*v4*v3^3+v6*v5^2*v4*v3^3+2*v6^2*v5*v3^4+2*v5^3*v3^4-2*v6*v5*v4^3*v3*v11-4*v6^2*v4^2*v3^2*v11-4*v5^2*v4^2*v3^2*v11-6*v6*v5*v4*v3^3*v11-2*v6^2*v3^4*v11-6*v5^2*v3^4*v11+v5*v4^4*v11^2+5*v6*v4^3*v3*v11^2+7*v5*v4^2*v3^2*v11^2+5*v6*v4*v3^3*v11^2+6*v5*v3^4*v11^2-2*v4^4*v11^3-4*v4^2*v3^2*v11^3-2*v3^4*v11^3]
aa:=eliminate([-1*v10^2+-1*v9^2+2*v10*v8+2*v9*v7+-2*v8*v6+v6^2+-2*v7*v5+v5^2,-1*v9*v4+v10*v3,v10*v4+-1*v8*v4+v9*v3+-1*v7*v3,-1*v14^2+-1*v13^2+2*v14*v12+2*v13*v11+-2*v12*v6+v6^2+-2*v11*v5+v5^2,v13*v4+-1*v14*v3,v14*v4+-1*v12*v4+v13*v3+-1*v11*v3,2*v15+-1*v13+-1*v5,2*v16+-1*v14+-1*v6,-1*v18+v12+v3,-1*v17+v11+-1*v4,-1*v19*v4+v20*v3,v19*v18+-1*v20*v17+-1*v19*v12+v17*v12+v20*v11+-1*v18*v11,2*v23+-1*v21+-1*v5,2*v24+-1*v22+-1*v6,v23*v16+-1*v24*v15+-1*v23*v12+v15*v12+v24*v11+-1*v16*v11,-1*v26+-1*v15+v11+v6,-1*v25+v16+-1*v12+v5,-1*v25*v24+v26*v23+v25*v22+-1*v23*v22+-1*v26*v21+v24*v21,1+-1*v29*v22+-1*v29*v21+v29^2*v22*v21+v29*v20+-1*v29^2*v21*v20+v29*v19+-1*v29^2*v22*v19+v29^2*v20*v19],revlist([v7,v8,v9,v10,v12,v13,v14,v15,v16,v17,v18,v19,v20,v21,v22,v23,v24,v25,v26,v29]))