Question

[ánh tuyết nguyễn]

1/ Giải phương trình sau:

\(tan^2\left(x+\dfrac{\pi}{3}\right)+\left(\sqrt{3}-1\right)tan\left(x+\dfrac{\pi}{3}\right)-\sqrt{3}=0\)

Answer 1

[Nguyễn Việt Lâm]

Đặt \(tan\left(x+\dfrac{\pi}{3}\right)=t\)

\(\Rightarrow t^2+\left(\sqrt{3}-1\right)t-\sqrt{3}=0\)

\(\Leftrightarrow t\left(t-1\right)+\sqrt{3}\left(t-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}t=1\\t=-\sqrt{3}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}tan\left(x+\dfrac{\pi}{3}\right)=1\\tan\left(x+\dfrac{\pi}{3}\right)=-\sqrt{3}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x+\dfrac{\pi}{3}=\dfrac{\pi}{4}+k\pi\\x+\dfrac{\pi}{3}=-\dfrac{\pi}{3}+k\pi\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=-\dfrac{\pi}{12}+k\pi\\x=-\dfrac{2\pi}{3}+k\pi\end{matrix}\right.\)