ABCD is a straight line O is a point so that OA = a and OB = b B is the midpoint of AC C is the midpoint of AD Express in terms of a and b the vectors: (i) AC (ii) OD
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Originally Posted by Danielisew ABCD is a straight line O is a point so that OA = a and OB = b B is the midpoint of AC C is the midpoint of AD Express in terms of a and b the vectors: (i) AC (ii) OD (i) So $\displaystyle \vec{AC}=2\vec{AB}$ and $\displaystyle \vec{AB}=-\bold{a}+\bold{b}$ (ii) $\displaystyle \vec{OD}=\bold{a}+2 \vec{AC}$ and from these you should be able to complete the answers yourself. RonL
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