Question

va rog ajutati ma dau coroana ​

Answer 1

Răspuns:

Explicație pas cu pas:

Answer 2

Fie AD ⊥ BC, (D ∈ BC), O - centrul cercului circumscris, O∈ AD ⇒

⇒ OD = (1/2)AO

$\it \left\begin{aligned}\overrightarrow{AB}+\overrightarrow{BD}=\overrightarrow{AD}\\ \\ \overrightarrow{AC}+\overrightarrow{CD}=\overrightarrow{AD}\end{aligned}\right\} \Rightarrow \overrightarrow{AB}+\underbrace{(\overrightarrow{BD}+\overrightarrow{CD})}_{=\overrightarrow{0}}+\overrightarrow{AC}=2\overrightarrow{AD} \Rightarrow$

$\it \Rightarrow \overrightarrow{AB}+\overrightarrow{AC}=2(\overrightarrow{AO}+\overrightarrow{OD})=2(\overrightarrow{AO}+\dfrac{1}{2}\overrightarrow{AO})=2\overrightarrow{AO}+\overrightarrow{AO}=3\overrightarrow{AO}$