Cho A(1;

B

- Hướng dẫn giải

Đáp án B

$\tan \widehat{AOx}=\frac{\sqrt{3}}{1} = \sqrt{3}\Rightarrow \widehat{(OA;\text{Ox)}}={30}^o$ 

$$\begin{gathered} \Rightarrow \widehat{AOy}= {90}^0- {60}^0= {30}^0 \\ \Rightarrow \widehat{A\text{'}Oy}= {75}^0- {30}^0={45}^o \end{gathered}$$

Mà $OA = \sqrt{ {\left(\sqrt{3}\right)}^2+\hspace{0.17em}{1}^2} = 2$$\Rightarrow OA\text{'}=2$$\Rightarrow A\text{'}(-\sqrt{2};\sqrt{2})$