## anonymous 5 years ago f(x,y)= x^2-y^2+xy-10x+3

1. nikvist

what's the question?

2. anonymous

to find critical point and also to determent max, min or saddle point..???

3. nikvist

$f(x,y)= x^2-y^2+xy-10x+3$ $f'_x(x,y)= 2x+y-10=0$ $f'_y(x,y)= -2y+x=0$ $\rightarrow x=4,y=2$ $f''_x(x,y)= 2,f''_y(x,y)= -2$$f''_{xy}(x,y)=f''_{yx}(x,y)=1$ $Hessian=-2*2-1=-5$ (4,2) is saddle point