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If I have three vectors
a=2i-j+k
b=xi+j+3k
c=-2i+yj-zk
and they make different edges of a parallelpiped, how do I find out x,y and z so that the parallelpiped is ortogonal.
If the edges are orthogonal then the dot products of the vectors are zero. You have three possible dot products between pairs of vectors, and therefore you have three equations. Put them in a solve block and solve for x, y, and z.