I have two points in cartesian coordinates P_1=(1,0,2) and P_2=(0,2,1) and need the distance vector from P_1 to point P_2. The vector from origin to P_1 is defined as R while the vector from origin to point P_2 is defined as bb(R'). The vector I am looking for is then bb(R-R') between the first and the second one in space. I have forgotten linear algebra a bit so I am not sure of the proper way of doing it. Could you please help me out?

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