№1.12. Given the vector. It is necessary: ​​a) to calculate the mixed product of the three vectors; b) find the module of the vector product; c) calculate the scalar product of two vectors; d) check whether the two vectors are collinear or orthogonal; e) check whether the three vectors are coplanar: a (-4; 3; -7); b (4; 6; -2); c (6; 9; -3).
№2.12. The vertices of the pyramid are at points A (7; 4; 9); B (1; –2; –3); C (–5; –3; 0); D (1; –3; 4)
№ 3.12. The force F (2; 2; 9) is applied to the point A (4; 2; –3). Calculate a) the work force F in the case; when the point of its application; moving straight; moves to point B (2; 4; 0); b) the modulus of momentum of force F relative to point B.