Prove using vectors: Medians of a triangle are concurrent.

Explanation

`P` divides AD in ratio `2: 1`


`1 \cdot \vec{a}+2(\frac{\vec{b}+\vec{c}}{2}) / 2+1 `


`=\frac{\vec{a}+\vec{b}+\vec{c}}{3}=\frac{\vec{a}+\vec{b}}{2}`


since median divides other one in `2: 1`other one in `2: 1`.

For `B E:-\frac{1 \vec{b}+(\frac{2(\vec{c}+\vec{a})}{2})}{2+1}=\frac{\vec{a}+\vec{b}+\vec{c}}{3})`

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