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# Pure 3 Vector Equation Question watch

1. If you have a 3d cartesian equation, could you put it into a vector equation? But how would you get translation, points etc? Cos you can't just say x = 0 cos you have y and z still to work out?

e.g. x - 2y +3z - 7 =0

Now could I put this into a vector equation?

Cheers
2. Vector equation is (xi+yj+zk).(i-2j+3k) = 7
To find a point on the plane you can choose 2 values of x and y (say 1 and 1) then find the corresponding z value (in this case 3) so (1,1,3) is on the plane
3. Hmmm, I can go from vector form to cartesian form of a plane, but back the other way, i would just use the equation to find three points on the plane, and then work it out that way.
4. To go from cartesian to vector you must remember that

r.n = a.n

and also if you have the cartesian equation, Ax + By + Cz = k

then (A B C) is the normal to that plane, ie n

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Updated: June 13, 2004
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