№1.15. 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; 2; -3); b (0; -3; 5); c (6; 6; -4).
No. 2.15. The vertices of the pyramid are at the points A (5; 2; 4); B (–3; 5; –7); C (1; –5; 8); D (9; –3; 5) .. .... ..
№3.15. Three forces P are given (9; –3; 4); Q (5; 6; –2); R (–4; –2; 7); applied to point A (–5; 4; –2). Calculate a) the work done by the resultant of these forces; when the point of its application, moving in a straight line, moves to point B (4; 6; –5); b) size
the moment of the resultant of these forces relative to point B.