Quan hệ giữa các giá trị lượng giác của hai góc đặc biệt — Không quảng cáo

$\sin ( - \alpha ) =  - \sin \alpha$;

$\tan ( - \alpha ) =  - \tan \alpha$

$\cos ( - \alpha ) = \cos \alpha$;

$\cot ( - \alpha ) =  - \cot \alpha$

$\sin \left( {{{90}^ \circ } - \alpha } \right) = \cos \alpha$;

$\tan \left( {{{90}^ \circ } - \alpha } \right) = \cot \alpha$

$\cos \left( {{{90}^ \circ } - \alpha } \right) = \sin \alpha$;

$\cot \left( {{{90}^ \circ } - \alpha } \right) = \tan \alpha$

$\sin \left( {{{180}^ \circ } - \alpha } \right) = \sin \alpha$;

$\tan \left( {{{180}^ \circ } - \alpha } \right) =  - \tan \alpha$

$\cos \left( {{{180}^ \circ } - \alpha } \right) =  - \cos \alpha$;

$\cot \left( {{{180}^ \circ } - \alpha } \right) =  - \cot \alpha$

$\sin \left( {{{90}^ \circ } + \alpha } \right) = \cos \alpha$;

$\tan \left( {{{90}^ \circ } + \alpha } \right) =  - \cot \alpha$

$\cos \left( {{{90}^ \circ } + \alpha } \right) =  - \sin \alpha$;

$\cot \left( {{{90}^ \circ } + \alpha } \right) =  - \tan \alpha$

$\sin \left( {{{180}^ \circ } + \alpha } \right) =  - \sin \alpha$;

$\tan \left( {{{180}^ \circ } + \alpha } \right) = \tan \alpha$

$\cos \left( {{{180}^ \circ } + \alpha } \right) =  - \cos \alpha$;

$\cot \left( {{{180}^ \circ } + \alpha } \right) = \cot \alpha$

$\sin \left( {2k{{.180}^ \circ } + \alpha } \right) = \sin \alpha$;

$\tan \left( {k{{.180}^ \circ } + \alpha } \right) = \tan \alpha$

$\cos \left( {2k{{.180}^ \circ } + \alpha } \right) = \cos \alpha$;

$\cot \left( {k{{.180}^ \circ } + \alpha } \right) = \cot \alpha$