... M2 = (- ^2 ! } '2 > ^2) ^^ ^^ ^ ^^y >*' ^1- ^2+ yi> '2+ ^1 ^2 COS(M] , M2) = ^x\+y1 + z\ yjxj+yj+zl H23 Khi nao hai vecto vudng gdc vdi ? • GV neu he qua : M] J U2 o iii.ii2 = 'i - >' '2; ^i - ^2) 4) kn^ = (A-A'i; ky^ ; fe,) 5) N|.U2 = Vj.vo + 3'iy2 + z,Z2 6) K | = ... Viet phuong trinh mat ciu H.hoc 12/ 2 Ggi y trd Idi cdu hoi I a = 1, b = -2 vac = Ggi y trd loi cdu hdi r = Ggi y trd Idi cdu hdi (x-l )2+ (y + 2) 2 +(z-3)^ =25 49 H27 Hay neu mdt dang khac ciia phuong...