Question 1092170
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It is the vector (1,-2,-2) normalized (scaled) by its length d = {{{sqrt(1^2 + (-2)^2 + (-2)^2)}}} = {{{sqrt(1+4+4)}}} = {{{sqrt(9)}}} = 3.


So, the unit vector under the question is ({{{1/3}}},{{{-2/3}}},{{{-2/3}}}).
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