10 Bài tập Giải một số phương trình lượng giác đưa về phương trình lượng giác cơ bản (có lời giải)

A. $\left[\begin{array}{l}x=\frac{\pi }{6}+k2\pi \\ x=\frac{5\pi }{6}+k2\pi \end{array}\right.$ , k ∈ ℤ;

B. $\left[\begin{array}{l}x=\pi +k2\pi \\ x=k2\pi \end{array}\right.$ , k ∈ ℤ;

C. $x=k\pi$, k ∈ ℤ;

D. $x=k2\pi$, k ∈ ℤ.

A. x = $\frac{\pi }{2}+k2\pi$, k ∈ ℤ;

B. x = $\frac{\pi }{3}+k2\pi$, k ∈ ℤ;

C. x = $\frac{\pi }{2}+k\pi$, k ∈ ℤ;

D. x = $\frac{\pi }{6}+k2\pi$, k ∈ ℤ.

A. $\frac{\pi }{4}$;          

B. $\frac{\pi }{3}$;                    

C. $\frac{\pi }{2}$;          

D. $\frac{\pi }{6}$.

A. S = $\left\{k2\pi |k\in \mathbb{Z}\right\}$;

B. S = $\left\{k\pi |k\in \mathbb{Z}\right\}$;

C. S = $\left\{k\frac{2}{3}\pi ;x=\frac{\pi }{6}+k\frac{2}{3}\pi |k\in \mathbb{Z}\right\}$;

D. S = $\left\{k2\pi ;x=\frac{\pi }{6}+k2\pi |k\in \mathbb{Z}\right\}$.

A. $\left[\begin{array}{l}x=\frac{\pi }{4}+k2\pi \\ x=\frac{5\pi }{6}+k2\pi \end{array}\right.$, k ∈ ℤ;

B. $\left[\begin{array}{l}x=\frac{\pi }{2}+k2\pi \\ x=\frac{7\pi }{6}+k2\pi \end{array}\right.$, k ∈ ℤ;

C. $\left[\begin{array}{l}x=\frac{\pi }{3}+k2\pi \\ x=\frac{\pi }{6}+k2\pi \end{array}\right.$, k ∈ ℤ;

D. $\left[\begin{array}{l}x=\frac{\pi }{2}+k\pi \\ x=\frac{7\pi }{6}+k\pi \end{array}\right.$, k ∈ ℤ.

A. $\frac{\pi }{4}$;          

B. $\frac{\pi }{8}$;          

C. $\frac{\pi }{2}$;          

D. $\frac{\pi }{16}$.

A. S = $\left\{\frac{\pi }{3}+k\pi ;\frac{\pi }{4}+k\pi |k\in \mathbb{Z}\right\}$;

B. S = $\left\{\frac{\pi }{6}+k\pi ;\frac{\pi }{4}+k\pi |k\in \mathbb{Z}\right\}$;

C. S =$\left\{\frac{\pi }{3}+k\pi ;\frac{\pi }{5}+k\pi |k\in \mathbb{Z}\right\}$;

D. S =$\left\{\frac{5\pi }{6}+k\pi ;\frac{\pi }{4}+k\pi |k\in \mathbb{Z}\right\}$.

A. $\left[\begin{array}{l}x=-\frac{\pi }{4}+k\pi \\ x=\frac{\pi }{6}+k\pi \\ x=-\frac{\pi }{6}+k\pi \end{array}\right.$, k ∈ ℤ;

B. $\left[\begin{array}{l}x=\frac{\pi }{4}+k\pi \\ x=\frac{\pi }{6}+k\pi \\ x=-\frac{\pi }{6}+k\pi \end{array}\right.$, k ∈ ℤ;

C. $\left[\begin{array}{l}x=-\frac{\pi }{4}+k\pi \\ x=\frac{\pi }{6}+k\pi \\ x=\frac{5\pi }{6}+k\pi \end{array}\right.$, k ∈ ℤ;

D. $\left[\begin{array}{l}x=-\frac{3\pi }{4}+k\pi \\ x=\frac{\pi }{6}+k\pi \\ x=-\frac{\pi }{6}+k\pi \end{array}\right.$, k ∈ ℤ.

A. $\left[\begin{array}{l}x=\frac{\pi }{4}+k2\pi \\ x=-\frac{\pi }{4}+k2\pi \end{array}\right.$, k ∈ ℤ;

B. $\left[\begin{array}{l}x=\frac{\pi }{4}+k2\pi \\ x=-\frac{\pi }{3}+k2\pi \end{array}\right.$, k ∈ ℤ;

C. $\left[\begin{array}{l}x=\frac{\pi }{6}+k2\pi \\ x=-\frac{\pi }{3}+k2\pi \end{array}\right.$, k ∈ ℤ;

D. $\left[\begin{array}{l}x=\frac{\pi }{2}+k2\pi \\ x=-\frac{\pi }{2}+k2\pi \end{array}\right.$, k ∈ ℤ.