Nếu x , α là góc lượng giác có đơn vị là rađian thì A. tan x = tan α ⇔ x = α + k π , k ∈ Z . B. tan x = tan α ⇔ x = π − α + k π , k ∈ Z .

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

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

\(\tan x = \tan \alpha \Leftrightarrow \left[ {\begin{array}{*{20}{l}}{x = \alpha + k2\pi }\\{x = \pi - \alpha + k2\pi }\end{array},k \in \mathbb{Z}} \right..\)

\(\tan x = \tan \alpha \Leftrightarrow \left[ {\begin{array}{*{20}{l}}{x = \alpha + k2\pi }\\{x = - \alpha + k2\pi }\end{array},k \in \mathbb{Z}} \right..\)