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Oct3-03, 11:12 AM
P: 1,046
What if A is the zero vector? Then A.B=A.C no matter what B and C are.

And even if A <> 0 if you break A, B and C down into components, I think you will find that you can come up with other situations where A.(B-C) must equal 0 even though you know nothing about the values of B and C individually.

Try it.