x = (cos(a)*sqrt(L^2*cos(a)^2*sin(a)^2*tan(a)^2-2*L^2*cos(a)*sin(a)*tan(a)+(L^2+2*D*L+D^2)*cos(a)^2*sin(a)^2-L^2*cos(a)^2+L^2)+((-L)-D)*cos(a)^2*sin(a)^2*tan(a)+(L+D)*cos(a)*sin(a))/(cos(a)^2*sin(a)^2*tan(a)^2-2*cos(a)*sin(a)*tan(a)-cos(a)^2+1)
r = ((cos(a)*sin(a)*tan(a)-1)*sqrt(L^2*cos(a)^2*sin(a)^2*tan(a)^2-2*L^2*cos(a)*sin(a)*tan(a)+(L^2+2*D*L+D^2)*cos(a)^2*sin(a)^2-L^2*cos(a)^2+L^2)+((-L)-D)*cos(a)^2*sin(a))/(cos(a)^2*sin(a)^2*tan(a)^2-2*cos(a)*sin(a)*tan(a)-cos(a)^2+1)