Number 1 are given the vector. It is necessary: ​​a) to calculate the mixed product of three vectors; b) find the modulus of the vector product; c) calculate the scalar product of two vectors; d) check whether two vectors are collinear or orthogonal; e) check whether the three vectors are coplanar. a (7; -4; -5); b (1; -11; 3); c (5; 5; 3).

No. 2 The vertices of the pyramid are located at points A (–2; –5; –1); B (–6; –7; 9); C (4; –5; 1); D (2; 1; 4) ...

No. 3 Given three forces P (7; 3; –4); Q (9; –4; 2); R (–6; 1; 4); applied to point A (–7; 2; 5). Calculate a) the work produced by the resultant of these forces; when the point of its application, moving rectilinearly, moves to point B (4; –2; 11); b) the magnitude of the moment of the resultant of these forces relative to point B.