Đáp án+Giải thích các bước giải:
$sin^2\beta+cos^2\beta=1$
$⇒cos\beta=\sqrt{1-sin^2\beta}$
$⇒cos\beta=\sqrt{1-(\dfrac{1}{2})^2}=\dfrac{\sqrt{3}}{2}$
$tan\beta=\dfrac{sin\beta}{cos\beta}=\dfrac{\dfrac{1}{2}}{\dfrac{\sqrt{3}}{2}}=\dfrac{\sqrt{3}}{3}$
Vậy $\begin{cases}cos\beta=\dfrac{\sqrt{3}}{2}\\tan\beta=\dfrac{\sqrt{3}}{3}\end{cases}$