Câu hỏi:

Giải phương trình $8\sin x=\frac{\sqrt{3}}{\cos x}+\frac{1}{\sin x}$

$x=-\frac{\mathrm{\pi }}{6}+\frac{k\mathrm{\pi }}{2}; x=\frac{\mathrm{\pi }}{12}+\frac{k\mathrm{\pi }}{2}\left(k\in Z\right)$

A. $x=\frac{\mathrm{\pi }}{12}+\frac{k\mathrm{\pi }}{4}\left(k\in Z\right)$

B. $x=\pm \frac{\mathrm{\pi }}{6}+k\mathrm{\pi }; x=-\frac{\mathrm{\pi }}{12}+\frac{k\mathrm{\pi }}{2}\left(k\in Z\right)$

C. $x=-\frac{\mathrm{\pi }}{6}+k\mathrm{\pi }; x=-\frac{\mathrm{\pi }}{12}+\frac{k\mathrm{\pi }}{2}\left(k\in Z\right)$ 

Câu 1:

Giải phương trình $2si{n}^{2}2x+sin7x-1=sinx$

$x=-\frac{\mathrm{\pi }}{18}+\frac{k\mathrm{\pi }}{3}; x=\frac{5\mathrm{\pi }}{18}+\frac{k2\mathrm{\pi }}{9}$

A. $x=\pm \frac{\mathrm{\pi }}{18}+k2\mathrm{\pi }; x=\frac{5\mathrm{\pi }}{18}+\frac{k2\mathrm{\pi }}{3}$

B. $x=\frac{\mathrm{\pi }}{8}+\frac{k\mathrm{\pi }}{4}; x=\frac{\mathrm{\pi }}{18}+\frac{k2\mathrm{\pi }}{3}; x=\frac{5\mathrm{\pi }}{18}+\frac{k2\mathrm{\pi }}{3}$

C. $x=\frac{\mathrm{\pi }}{8}+\frac{k\mathrm{\pi }}{4}; x=\frac{\mathrm{\pi }}{18}+\frac{k\mathrm{\pi }}{18}; x=-\frac{5\mathrm{\pi }}{18}+\frac{k\mathrm{\pi }}{3}$

Câu 2:

Phương trình $\sqrt{3}\sin 2x-\cos 2x+1=0$ có nghiệm là

$\left[\begin{array}{l}x=k\pi \\ x=\frac{\pi }{3}+k\pi \end{array}\right.(k\in Z)$

A. $\left[\begin{array}{l}x=k\pi \\ x=\frac{2\pi }{3}+k2\pi \end{array}\right.(k\in Z)$

B. $\left[\begin{array}{l}x=k2\pi \\ x=\frac{2\pi }{3}+k2\pi \end{array}\right.(k\in Z)$

C. $\left[\begin{array}{l}x=k\pi \\ x=\frac{2\pi }{3}+k\pi \end{array}\right.(k\in Z)$ 

Câu 3:

Giải phương trình $si{n}^{2}x+sin2x.sin4x+sin3x.sin9x+sin4x.sin16x=1$

$x=\frac{\mathrm{\pi }}{22}+\frac{k\mathrm{\pi }}{8}\left(k\in Z\right)$

A. $x=\frac{\mathrm{\pi }}{16}+\frac{k\mathrm{\pi }}{10}\left(k\in Z\right)$

B. $x=\frac{\mathrm{\pi }}{20}+\frac{k\mathrm{\pi }}{10}\left(k\in Z\right)$

C. $x=\frac{k\mathrm{\pi }}{4},x=\frac{\mathrm{\pi }}{44}+\frac{k\mathrm{\pi }}{20}\left(k\in Z\right)$ 

Câu 4:

Phương trình $\sqrt{3}\cos 3x+\sin 3x=\sqrt{2}$ có nghiệm là:

A. $\left[\begin{array}{l}x=-\frac{\pi }{36}+\frac{k2\pi }{3}\\ x=\frac{5\pi }{36}+\frac{k2\pi }{3}\end{array}\right.(k\in Z)$

B. $\left[\begin{array}{l}x=-\frac{\pi }{36}+\frac{k\pi }{3}\\ x=\frac{5\pi }{36}+\frac{k\pi }{3}\end{array}\right.(k\in Z)$

C. $\left[\begin{array}{l}x=\frac{\pi }{36}+\frac{k2\pi }{3}\\ x=-\frac{5\pi }{36}+\frac{k2\pi }{3}\end{array}\right.(k\in Z)$

D. $\left[\begin{array}{l}x=-\frac{\pi }{36}+k2\pi \\ x=\frac{5\pi }{36}+k2\pi \end{array}\right.(k\in Z)$ 

Câu 5:

Phương trình ${\sin }^{2}3x+\left(m^2-3\right)\sin 3x+m^2-4=0$ khi m=1 có nghiệm là:

$x=-\frac{\pi }{6}+k2\pi \left(k\in Z\right)$

A. $x=\frac{\pi }{6}+\frac{k2\pi }{3}\left(k\in Z\right)$

B. $x=-\frac{\pi }{6}+\frac{k2\pi }{3}\left(k\in Z\right)$

C. $x=\pm \frac{\pi }{6}+\frac{k2\pi }{3}\left(k\in Z\right)$ 

Câu 6:

Phương trình ${\cos }^{2}x-4\cos x+3=0$ có nghiệm là:

$x=\pi +k2\pi \left(k\in Z\right)$

A. $x=k\pi \left(k\in Z\right)$

B. $x=\pi +k\pi \left(k\in Z\right)$

C. $x=k2\pi \left(k\in Z\right)$