... (1,5 ): im dng M1(1 ,2) , M2 (- 1, - 2) , M3 (2, 1), M4 (- 2, - 1) (0.5) Cc tr : fmin = f (2, 1) = - 28 , fmax = f (- 2, - 1) = 28 (0.5) K t cc tr ti M1, M2 (0.5) Cõu (1) Hi t theo t/c Cauchy Ơ (- 1)n ... fx = xe y - xye x ù Cõu (1,5 ): Tớnh (0.5) ù y x2 ù fy = x e - e ù  ù ợ 2 ỡ ù  ù fxx = 2e y - 2ye x - x ye x  ù Tớnh (0.5) Suy d 2f (0,1) = (e - 2) dx 2 ù ù fyy = x 2e y , fxy = xe y - xe x  ... bi 0y4-x2-z2 (0.5) p dng CT Gauss ta cú 2 ũũ x dydz + 2ydzdx + z dxdy = - ũũũ (2 x + + 2z )dxdydz SUS1 V 2p 4- r I = - ũ dj ũ rdr ũ (1 + cos j + sin j )dy - (0.5) Vy I = -1 6 (0.5) 0 Cõu 7: (1.5)...