f(x,y,s)=x^2+2y^2-x+s(x^2+y^2-1)f'x = 2x -1 +2sx =0f'册逗碧y = 4y +2sy =0f's=x^2+y^2-1=0求解州举上述方程组得到的x,y点就是极值指哪点
