Phương trình sin x = sin α có nghiệm là

\[\left[ \begin{array}{l}x = \alpha + k2\pi \\x = \pi - \alpha + k2\pi \end{array} \right.;k \in \mathbb{Z}\]

\[\left[ \begin{array}{l}x = \alpha + k\pi \\x = \pi - \alpha + k\pi \end{array} \right.;k \in \mathbb{Z}\].

\[\left[ \begin{array}{l}x = \alpha + k\pi \\x = - \alpha + k\pi \end{array} \right.;k \in \mathbb{Z}\].

\[\left[ \begin{array}{l}x = \alpha + k2\pi \\x = - \alpha + k2\pi \end{array} \right.;k \in \mathbb{Z}\].