A. \(\cot 2x = \frac{{{{\cot }^2}x - 1}}{{2\cot x}}\)
B. \(\tan 2x = \frac{{2\tan x}}{{1 + {{\tan }^2}x}}\)
C. \(\cos 3x = 4{\cos ^3}x - 3\cos x\)
D. \(\sin 3x = 3\sin x - 4{\sin ^3}x\)
A. \(\cos \left( {a--b} \right) = \cos a.\cos b + \sin a.\sin b.\)
B. \(\cos \left( {a + b} \right) = \cos a.\cos b + \sin a.\sin b.\)
C. \(\sin \left( {a--b} \right) = \sin a.\cos b + \cos a.\sin b.\)
D. \(\sin \left( {a + b} \right) = \sin a.\cos b - \cos .\sin b.\)
A. \(\tan \left( {a - b} \right) = \frac{{\tan a + \tan b}}{{1 - \tan a\tan b}}.\)
B. \(\tan \left( {a--b} \right) = \tan a - \tan b.\)
C. \(\tan \left( {a + b} \right) = \frac{{\tan a + \tan b}}{{1 - \tan a\tan b}}.\)
D. \(\tan \left( {a + b} \right) = \tan a + \tan b.\)
A. \(\cos a\cos b = \frac{1}{2}\left[ {\cos \left( {a--b} \right) + \cos \left( {a + b} \right)} \right].\)
B. \(\sin a\sin b = \frac{1}{2}\left[ {\cos \left( {a--b} \right)--\cos \left( {a + b} \right)} \right].\)
C. \(\sin a\cos b = \frac{1}{2}\left[ {\sin \left( {a--b} \right) + \sin \left( {a + b} \right)} \right].\)
D. \(\sin a\cos b = \frac{1}{2}\left[ {\sin \left( {a - b} \right) - \cos \left( {a + b} \right)} \right].\)
A. \(\cos a + \cos b = 2\cos \frac{{a + b}}{2}.\cos \frac{{a - b}}{2}.\)
B. \(\cos a--\cos b = 2\sin \frac{{a + b}}{2}.\sin \frac{{a - b}}{2}.\)
C. \(\sin a + \sin b = 2\sin \frac{{a + b}}{2}.\cos \frac{{a - b}}{2}.\)
D. \(\sin a--\sin b = 2\cos \frac{{a + b}}{2}.\sin \frac{{a - b}}{2}.\)
A. \(\sin 2a.\)
B. \(\cos 2a.\)
C. \( - \frac{1}{2}.\)
D. \( \frac{1}{2}.\)
A. \(\frac{{\sqrt 6 + \sqrt 2 }}{4}.\)
B. \(\frac{{\sqrt 6 - \sqrt 2 }}{4}.\)
C. \(-\frac{{\sqrt 6 + \sqrt 2 }}{4}.\)
D. \(\frac{{\sqrt 2 - \sqrt 6 }}{4}.\)
A. \(\frac{{\sqrt 3 }}{2}.\)
B. \(-\frac{{\sqrt 3 }}{2}.\)
C. \(\frac{{\sqrt 2 }}{2}.\)
D. \( - \frac{1}{2}.\)
A. \(\frac{{\sqrt 3 }}{2}.\)
B. \(-\frac{{\sqrt 3 }}{2}.\)
C. \(\frac{1}{2}.\)
D. \(-\frac{1}{2}.\)
A. 1
B. - 1
C. \(\frac{{\sqrt 3 }}{3}.\)
D. \(\sqrt 3 .\)
A. \(\frac{{\sqrt 2 }}{2},\frac{{\sqrt 3 }}{2}\)
B. \(\frac{{-\sqrt 2 }}{2},\frac{{\sqrt 3 }}{2}\)
C. \(\frac{{\sqrt 2 }}{2},-frac{{\sqrt 3 }}{2}\)
D. \(-\frac{{\sqrt 2 }}{2},-\frac{{\sqrt 3 }}{2}\)
A. \(\frac{1}{2}.\)
B. \(-\frac{1}{2}.\)
C. \(\frac{1}{4}.\)
D. \(-\frac{1}{4}.\)
A. \(2\left( {\sqrt 6 - \sqrt 3 } \right).\)
B. \(2\left( {\sqrt 6 + \sqrt 3 } \right).\)
C. \(2\left( {\sqrt 3 - \sqrt 2 } \right).\)
D. \(2\left( {\sqrt 3 + \sqrt 2 } \right).\)
A. 1
B. - 1
C. 2
D. - 2
A. \(\frac{1}{{16}}.\)
B. \(\frac{1}{{8}}.\)
C. \(\frac{3}{{16}}.\)
D. \(\frac{1}{{4}}.\)
A. \(\frac{1}{8}.\)
B. \(-\frac{1}{8}.\)
C. \(\frac{1}{4}.\)
D. \(-\frac{1}{4}.\)
A. \(\frac{2}{{\sqrt 3 }}.\)
B. \(\frac{4}{{\sqrt 3 }}.\)
C. \(\frac{6}{{\sqrt 3 }}.\)
D. \(\frac{8}{{\sqrt 3 }}.\)
A. 14
B. 16
C. 18
D. 10
A. \( - \frac{1}{2}.\)
B. \( \frac{1}{2}.\)
C. \( - \frac{{\sqrt 3 }}{2}.\)
D. \( \frac{{\sqrt 3 }}{2}.\)
A. 1
B. - 1
C. 0
D. \(\frac{1}{2}.\)
A. \(\cos 50^\circ .\)
B. \(\cos 58^\circ .\)
C. \(\sin 50^\circ .\)
D. \(\sin 58^\circ .\)
A. 4
B. - 4
C. 8
D. - 8
A. \(\frac{\pi }{6}.\)
B. \(\frac{\pi }{5}.\)
C. \(\frac{\pi }{4}.\)
D. \(\frac{\pi }{3}.\)
A. \(\frac{\pi }{3}.\)
B. \(\frac{\pi }{4}.\)
C. \(\frac{\pi }{6}.\)
D. \(\frac{2\pi }{3}.\)
A. \(\frac{\pi }{4}.\)
B. \(\frac{3\pi }{4}.\)
C. \(\frac{\pi }{3}.\)
D. \(\pi\)
A. \(\frac{{11}}{{113}}.\)
B. \(\frac{{13}}{{113}}.\)
C. \(\frac{{15}}{{113}}.\)
D. \(\frac{{17}}{{113}}.\)
A. \(\frac{{2\sqrt 2 + 7\sqrt 3 }}{{18}}.\)
B. \(\frac{{3\sqrt 2 + 7\sqrt 3 }}{{18}}.\)
C. \(\frac{{4\sqrt 2 + 7\sqrt 3 }}{{18}}.\)
D. \(\frac{{5\sqrt 2 + 7\sqrt 3 }}{{18}}.\)
A. \(\frac{3}{4}.\)
B. \(\frac{4}{3}.\)
C. \(\frac{3}{2}.\)
D. \(\frac{2}{3}.\)
A. - 1
B. 1
C. - 2
D. 0
A. \(\frac{{\sin \left( {a + b} \right)}}{{\sin \left( {a - b} \right)}} = \frac{{\sin a + \sin b}}{{\sin a - \sin b}}.\)
B. \(\frac{{\sin \left( {a + b} \right)}}{{\sin \left( {a - b} \right)}} = \frac{{\sin a - \sin b}}{{\sin a + \sin b}}.\)
C. \(\frac{{\sin \left( {a + b} \right)}}{{\sin \left( {a - b} \right)}} = \frac{{\tan a + \tan b}}{{\tan a - \tan b}}.\)
D. \(\frac{{\sin \left( {a + b} \right)}}{{\sin \left( {a - b} \right)}} = \frac{{\cot a + \cot b}}{{\cot a - \cot b}}.\)
A. \(\sin \frac{{A + B + 3C}}{2} = \cos C.\)
B. \(\cos \left( {A + B--C} \right) = --\cos 2C.\)
C. \(\tan \frac{{A + B - 2C}}{2} = \cot \frac{{3C}}{2}.\)
D. \(\cot \frac{{A + B + 2C}}{2} = \tan \frac{C}{2}.\)
A. \(\cos \frac{{A + B}}{2} = \sin \frac{C}{2}.\)
B. \(\cos \left( {A + B + 2C} \right) = --\cos C.\)
C. \(\sin \left( {A + C} \right) = --\sin B.\)
D. \(\cos \left( {A + B} \right) = --\cos C.\)
A. \(\cos \frac{B}{2}\cos \frac{C}{2} - \sin \frac{B}{2}\sin \frac{C}{2} = \sin \frac{A}{2}.\)
B. \(\tan A + \tan B + \tan C = \tan A.\tan B.\tan C.\)
C. \(\cot A + \cot B + \cot C = \cot A.\cot B.\cot C.\)
D. \(\tan \frac{A}{2}.\tan \frac{B}{2} + \tan \frac{B}{2}.\tan \frac{C}{2} + \tan \frac{C}{2}.\tan \frac{A}{2} = 1.\)
A. \(\frac{{\sqrt 5 }}{3}.\)
B. \(\frac{5}{{\sqrt 3 }}.\)
C. \(\frac{{\sqrt 3 }}{5}.\)
D. \(\frac{3}{{\sqrt 5 }}.\)
A. \(\frac{{3\sin \alpha }}{{5 - 3\cos \alpha }}.\)
B. \(\frac{{3\sin \alpha }}{{5 + 3\cos \alpha }}.\)
C. \(\frac{{3\cos \alpha }}{{5 - 3\cos \alpha }}.\)
D. \(\frac{{3\cos \alpha }}{{5 + 3\cos \alpha }}.\)
A. \(\frac{{\cos \left( {4\alpha + 30^\circ } \right)}}{{\cos \left( {4\alpha - 30^\circ } \right)}}.\)
B. \(\frac{{\cos \left( {4\alpha - 30^\circ } \right)}}{{\cos \left( {4\alpha + 30^\circ } \right)}}.\)
C. \(\frac{{\sin \left( {4\alpha + 30^\circ } \right)}}{{\sin \left( {4\alpha - 30^\circ } \right)}}.\)
D. \(\frac{{\sin \left( {4\alpha - 30^\circ } \right)}}{{\sin \left( {4\alpha + 30^\circ } \right)}}.\)
A. \(\sin 33^\circ + \cos 60^\circ = \cos 3^\circ .\)
B. \(\frac{{\sin 9^\circ }}{{\sin 48^\circ }} = \frac{{\sin 12^\circ }}{{\sin 81^\circ }}.\)
C. \(\cos 20^\circ + 2{\sin ^2}55^\circ = 1 + \sqrt 2 \sin 65^\circ .\)
D. \(\frac{1}{{\cos 290^\circ }} + \frac{1}{{\sqrt 3 \sin 250^\circ }} = \frac{4}{{\sqrt 3 }}.\)
A. \(\tan \left( {\alpha + \beta } \right) = 2\tan \beta .\)
B. \(\tan \left( {\alpha + \beta } \right) = 3\tan \beta .\)
C. \(\tan \left( {\alpha + \beta } \right) = 4\tan \beta .\)
D. \(\tan \left( {\alpha + \beta } \right) =5\tan \beta .\)
A. \(\frac{3}{5}\left( {1 + \frac{{\sqrt 7 }}{4}} \right).\)
B. \(-\frac{3}{5}\left( {1 + \frac{{\sqrt 7 }}{4}} \right).\)
C. \(\frac{3}{5}\left( {1 - \frac{{\sqrt 7 }}{4}} \right).\)
D. \(-\frac{3}{5}\left( {1 - \frac{{\sqrt 7 }}{4}} \right).\)
A. \(\frac{{24\sqrt 3 - 7}}{{50}}.\)
B. \(\frac{{7 - 24\sqrt 3 }}{{50}}.\)
C. \(\frac{{22\sqrt 3 - 7}}{{50}}.\)
D. \(\frac{{7 - 22\sqrt 3 }}{{50}}.\)
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