Question

giải pt : \(2cos\left(2x-1\right)-1=0\)

Answer 1

\(\Leftrightarrow cos\left(2x-1\right)=\dfrac{1}{2}\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-1=\dfrac{\pi}{3}+k2\pi\\2x-1=-\dfrac{\pi}{3}+k2\pi\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}+\dfrac{\pi}{6}+k\pi\\x=\dfrac{1}{2}-\dfrac{\pi}{6}+k\pi\end{matrix}\right.\)