DHS - 2.2
No. 1.20. 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 will be coplanar. a (-9; 4; -5); b (1; -2; 4); c (-5; 10; -20)
№2.20. The vertices of the pyramid are at points A (7; –1; –2); B (1; 7; 8); C (3; 7; 9); D (–3; –5; 2) ........
№3.20. Three forces P are given (3; –4; 2); Q (2; 3; –5); R (–3; –2; 4); attached to point A (5; 3; –7). Calculate a) the work produced by the resultant of these forces; when the point of its application, moving rectilinearly, moves to the point B (4; –1; –4); b) size
the moment of the resultant of these forces relative to point B.