구 함수 f (x, y) = x x x x x x x x x x x x － y × y + 3 × x x x x x + 3 × y × y － 9x 의 극치

구 함수 f (x, y) = x x x x x x x x x x x x － y × y + 3 × x x x x x + 3 × y × y － 9x 의 극치

f (x) = x ^ 3 - y ^ 3 + 3 x & # 178; + 3y & # 178; - 9x x x x x x = 3x x & # 178; + 6x x - 9 = 3 (x & # 178; + 2x x x 3) = 3 (x x - 1) (x x + 3), f 'x x = 0 득 x = 1, - 3f' y = 3y & # 178; + 6 y = - 3y (y (y (y - 2), f = 0 0 으로 2y = 2x x x x x x x x (x x x x x x x x x x x x + 3), f = x x x x x x x x x x x x x x x x x x x x x x x = 6 - 6 y = 6 y = 6 y = 6 y = 6 y = 6 y = 6 y = 점 (1, 0), A = 12, C = 6, AC - B & # 178; > 0, A > 0...