A.\(\dfrac{1}{2}{\sin ^2}{25^ \circ }\)
B.\(\dfrac{1}{2}{\cos ^2}{55^ \circ }\)
C.\(\dfrac{1}{2}{\cos ^2}{25^ \circ }\)
D.\(\dfrac{1}{2}{\sin ^2}{65^ \circ }\)

A.\( - 3 - \sqrt 3 \)
B.\(2 - 3\sqrt 3 \)
C.\(\dfrac{{2\sqrt 3 }}{{\sqrt 3  - 1}}\,\)
D.\(\dfrac{{1 - \sqrt 3 }}{{\sqrt 3 }}\)

A.\(\tan \left( {\pi  - \alpha } \right) = \tan \alpha \)
B.\(\sin \left( {\pi  - \alpha } \right) =  - \sin \alpha \)
C.\(\cot \left( {\pi  - \alpha } \right) = \cot \alpha \)
D.\(\cos \left( {\pi  - \alpha } \right) =  - \cos \alpha \)

A.\( - \sin \alpha \)
B.\( - \cos \alpha \)
C.\(\sin \alpha \)
D.\(\cos \alpha \)

A.\( - \dfrac{2}{3}\)
B.\( - \dfrac{1}{3}\)
C.\(\dfrac{1}{3}\)
D.\(\dfrac{2}{3}\)

A.\(\cot \alpha  = \cot \beta \)
B.\(\tan \alpha  =  - \tan \beta \)
C.\(\sin \alpha  = \sin \beta \)
D.\(\cos \alpha  =  - \cos \beta \)

A.\(A = \cos a + \sin a\)
B.\(A = 2\sin a\)
C.\(A = \sin a-\cos a\)
D.\(A = 0\)

A.\(3\sin \alpha  - 2\cos \alpha \)
B.\(3\sin \alpha \)
C.\( - 3\sin \alpha \)
D.\(2\cos \alpha  + 3\sin \alpha \)

A.\(\sqrt 3  - 2\)
B.\(\dfrac{{\sqrt {2 - \sqrt 3 } }}{2}\)
C.\(2 - \sqrt 3 \)
D.\(\dfrac{{2 + \sqrt 3 }}{4}\)

A.\(\cos \left[ {\dfrac{\pi }{4} + \left( {2k + 1} \right)\pi } \right] =  - \dfrac{{\sqrt 3 }}{2}\)
B.\(\cos \left[ {\dfrac{\pi }{4} + \left( {2k + 1} \right)\pi } \right] =  - \dfrac{{\sqrt 2 }}{2}\)
C.\(\cos \left[ {\dfrac{\pi }{4} + \left( {2k + 1} \right)\pi } \right] =  - \dfrac{1}{2}\)
D.\(\cos \left[ {\dfrac{\pi }{4} + \left( {2k + 1} \right)\pi } \right] = \dfrac{{\sqrt 3 }}{2}\)