Question

Bài 2 ạ

Answer 1

Ta có: \(\left\{{}\begin{matrix}BH\perp AC\\DC\perp AC\end{matrix}\right.\Rightarrow BH//CD\)

\(\left\{{}\begin{matrix}BD\perp AB\\HC\perp AB\end{matrix}\right.\Rightarrow BD//HC\)

\(\Rightarrow BDCH\) là hình bình hành

\(\Rightarrow DM=\dfrac{1}{2}DH\)

Khi đó: 

\(\vec{OM}=\vec{DM}-\vec{DO}=\dfrac{1}{2}\vec{DH}-\dfrac{1}{2}\vec{DA}=\dfrac{1}{2}\vec{AH}\)

\(\Rightarrow\vec{AH}=2\vec{OM}\)