Let , and be the position vectors of the vertices , and of a…

MATHEMATICS · Multi-part · CBSE · Mathematics · Vector Algebra · Vector Algebra

Problem

Let a\mathbf{a}, b\mathbf{b} and c\mathbf{c} be the position vectors of the vertices AA, BB and CC of a triangle. (i) Show that the midpoint MM of BCBC has position vector b+c2\dfrac{\mathbf{b}+\mathbf{c}}{2}. (ii) Prove that the centroid GG of △ABC\triangle ABC has position vector a+b+c3\dfrac{\mathbf{a}+\mathbf{b}+\mathbf{c}}{3}. (iii) Hence deduce that the centroid divides each median internally in the ratio 2:12:1.

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