Ryabushko A.P. IDZ 2.2 option 21

DHS - 2.2
№1.21.Dany vector. It is necessary to: a) calculate the mixed product of three vectors; b) Find the unit vector product; c) calculate the dot product of two vectors, and d) to check whether the collinear or orthogonal two vectors; e) verify whether the three vectors are coplanar. a (2, -7, 5); b (-1; 2; -6); c (3; 2; 4).
№2.21 top of the pyramid are located at points A (5, 2, 7); B (7, -6, -9); C (-7; -6; 3); D (1, -5, 2) ..........
№3.21. Given three forces P (4, -2, -5); Q (5; 1; 3); R (-6; 2; 5); applied to point A (-3, 2, -6). Calculate a) the work done by the resultant of these forces; when the point of its application, moving rectilinearly moves to point B (4; 5; 3); b) the value of
the resultant moment of the forces about point B.