x^(2)-2y^(2)+3z^(2)-yz+y=2 M0(1,1,1)
F(x;y;z)=0
F(x;y;z)=[b]x^2-2y^2+3z^2-yz-y-2[/b]
F`_(x)=2x
F`_(y)=-4y-z-1
F`_(z)=6z-y
z`_(x)=-F`_(x)/F`_(z)=-(2x)/(6z-y)
z`_(y)=-F`_(y)/F`_(z)=-(-4y-z-1)/(6z-y)
z`_(x)(M_(o))=-(2)/(6-1)=
z`_(y)(M_(o))=-(-4-1-1)/(6-1)=