Number 1 are given the vector. It is necessary: ​​a) to calculate the mixed product of 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 a (5; -6; -4) are coplanar; b (4; 8; -7); c (0; 3; -4).

No. 2 The vertices of the pyramid are located at points A (–4; –2; –3); B (2; 5; 7); C (6; 3; –1); D (6; –4; 1) ...
 
№3 Given three forces P (2; –1; –3); Q (3; 2; –1); R (–4; 1; 3); applied to point A (–1; 4; –2). Calculate a) the work produced by the resultant of these forces; when the point of its application, moving rectilinearly, moves to point B (2; 3; –1); b) the magnitude of the moment of the resultant of these forces relative to point B.