Hãy chọn khẳng định sai trong các khẳng định sau:

\(\cot x = \cot \alpha \Leftrightarrow x = \alpha + k\pi ,k \in \mathbb{Z}\).

\(\cos x = \cos \alpha \Leftrightarrow \left[ \begin{array}{l}x = \alpha + k2\pi \\x = - \alpha + k2\pi \end{array} \right.,k \in \mathbb{Z}\).

\(\sin x = \sin \alpha \Leftrightarrow \left[ \begin{array}{l}x = \alpha + k2\pi \\x = \pi - \alpha + k2\pi \end{array} \right.,k \in \mathbb{Z}\).

\(\tan x = \tan \alpha \Leftrightarrow x = \alpha + k2\pi ,k \in \mathbb{Z}\).