example15 := (-80-77*x^3+24*x^2*y+4*x^2-39*x*y^2+44*x*y-49*x+75*y^3+14*y^2+61* y)/(-29-17*x^3-90*x^2*y+13*x^2+68*x*y^2-84*x*y-81*x-60*y^3+68*y^2+11*y)*((70-\ 25*x^3-95*x^2*y-22*x^2+57*x*y^2+18*x*y+51*x+49*y^3+34*y^2-64*y)/(-63+97*x^3+21 *x^2*y-27*x^2-9*x*y^2+x*y+11*x+72*y^3-56*y^2+53*y))^(1/2)*exp(1);