Câu hỏi trắc nghiệm (10 câu):
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- A. \(\sin \left( a+b \right)=\sin a\cos b+\cos a\sin b\)
- B. \(\tan \left( a+b \right)=\frac{\tan a+\tan b}{1-\tan a\tan b}\)
- C. \(\cos \left( a-b \right)=\cos a\cos b - \sin a\sin b\)
- D. \(\tan \left( a-b \right)=\frac{\tan a-\tan b}{1+\tan a\tan b}\)
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- A. \(\frac{\sqrt{6}+\sqrt{2}}{4}\)
- B. \(\frac{\sqrt{6}-\sqrt{2}}{4}\)
- C. \(\frac{-\sqrt{6}+\sqrt{2}}{4}\)
- D. \(\frac{-\sqrt{6}-\sqrt{2}}{4}\)
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- A. \(\sin 2a=\sin a\cos a\)
- B. \(\cos 2a={{\cos }^{2}}a-{{\sin }^{2}}a=2{{\cos }^{2}}a-1=1+2{{\sin }^{2}}a\)
- C. \(\tan 2a=\frac{2\tan a}{1-{{\tan }^{2}}a}\)
- D. \(\cot 2a=\frac{{{\cot }^{2}}a+1}{2\cot a}\)
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- A. \(\frac{\sqrt{2}}{3}\)
- B. \(\frac{-\sqrt{2}}{3}\)
- C. \(\frac{2\sqrt{2}}{3}-\frac{1}{3}\)
- D. \(\frac{-2\sqrt{2}}{3}-\frac{1}{3}\)
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- A. \(-2\)
- B. \(-1\)
- C. 1
- D. 2
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- A. \(\cos a+\cos b=2\cos \frac{a+b}{2}\cos \frac{a-b}{2}\)
- B. \(\cos a-\cos a=2\sin \frac{a+b}{2}\sin \frac{a-b}{2}\)
- C. \(\sin a+\sin b=2\sin \frac{a+b}{2}\cos \frac{a-b}{2}\)
- D. \(\sin a-\sin b=2\cos \frac{a+b}{2}\sin \frac{a-b}{2}\)
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- A. \(\sin a\cos b=\frac{1}{2}\left[ \sin \left( a-b \right)+\sin \left( a+b \right) \right]\)
- B. \(\sin a\sin b=\frac{1}{2}\left[ \cos \left( a-b \right)-\cos \left( a+b \right) \right]\)
- C. \(\cos a\cos b=\frac{1}{2}\left[ \cos \left( a-b \right)+\cos \left( a+b \right) \right]\)
- D. Tất cả đều đúng.
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- A. \(a\)
- B. \(\frac{a}{2}\)
- C. \(\frac{4a\left( {{a}^{2}}-1 \right)\left( 3{{a}^{2}}-1 \right)}{{{\left( {{a}^{2}}+1 \right)}^{3}}}\)
- D. \(\frac{{{\left( {{a}^{2}}+1 \right)}^{3}}}{4a\left( {{a}^{2}}-1 \right)\left( 3{{a}^{2}}-1 \right)}\)
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- A. \( {{\sin }^{2}}a=\frac{1-\cos 2a}{2}\)
- B. \({{\cos }^{2}}a=\frac{1+\cos 2a}{2}\)
- C. \({{\tan }^{2}}a=\frac{1-\cos a}{1+\cos a} \)
- D. \({{\cot }^{2}}a=\frac{1+\cos 2a}{1-\cos 2a} \)
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- A. \(\sin 3x=3\sin x-4{{\sin }^{3}}x \)
- B. \( \cos 3x=4{{\cos }^{3}}x-3\cos x\)
- C. \( \tan 3x=\frac{3\tan x-{{\tan }^{3}}x}{1-3{{\tan }^{2}}x} \)
- D. Tất cả các câu trên đều đúng.
