Trắc nghiệm Một số phương trình lượng giác thường gặp có đáp án !!

A. x = π/3

B. x = π/4

C. x = π/6

D. x = 5 π/6

A. $\left\{-\frac{5\mathrm{\pi }}{6}+k\mathrm{\pi },\mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

B. $\left\{-\frac{5\mathrm{\pi }}{6}+k2\mathrm{\pi },\mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

C. $\left\{-\frac{\mathrm{\pi }}{2}+k\mathrm{\pi },\mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

D. $\left\{\frac{\mathrm{\pi }}{6}+k2\mathrm{\pi },\mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

A. 7π/8

B. 3π/8

C. π

D. 7π/4

A. $a\ge 2 hoặc a\le -\frac{1}{2}$

B. $a\ge \frac{1}{2} hoặc a\le -2$

C. $-\frac{1}{2}\le a\le 2$

D. $-1\le a\le \frac{1}{2}$

A. $k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc \frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc \frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. $\sin \left(2x-\frac{\mathrm{\pi }}{6}\right)=\frac{1}{2}$

B. $\sin \left(3x+\frac{\mathrm{\pi }}{6}\right)=\frac{\mathrm{\pi }}{6}$

C. $\sin \left(3x+\frac{\mathrm{\pi }}{6}\right)=-\frac{1}{2}$

D. $\sin \left(3x+\frac{\mathrm{\pi }}{6}\right)=\frac{1}{2}$

A. $m\le -4 hoặc m\ge 4$

B. m > 4

C. m < -4

D. -4 < m < 4

A. m = 4

B. m ≥ 4

C. m ≤ 4

D. m ∈R

A. x = π/6

B. x = π/2

C. x = 5π/2

D. x = 5π/6

A. $x=\pm \frac{2\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $x=\pm \frac{\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $x=\pm \frac{\mathrm{\pi }}{6}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $x=\pm \frac{\mathrm{\pi }}{6}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. 1

B. 2

C. 3

D. 4

A. 1

B. 2

C. 4

D. 6

A. $x=-\frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $x=-\frac{\mathrm{\pi }}{2}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $x=\frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $x=\mathrm{\pi }+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. $\frac{\mathrm{\pi }}{2}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc -\frac{\mathrm{\pi }}{4}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $\frac{\mathrm{\pi }}{2}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc \frac{\mathrm{\pi }}{4}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $\frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc -\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $\frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc \frac{\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. $k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} \mathrm{hoặc} -\frac{\mathrm{\pi }}{3}+\mathrm{k}2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} \mathrm{hoặc} \frac{\mathrm{\pi }}{3}+\mathrm{k\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} \mathrm{hoặc} -\frac{\mathrm{\pi }}{3}+k2\pi , \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} \mathrm{hoặc} -\frac{\mathrm{\pi }}{3}+\mathrm{k\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. $\left\{k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

B. $\left\{k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

C. $\left\{\frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

D. $\varnothing$

A. 7 π/4

B. 14π/4

C. 15π/8

D. 13π/4

A. 1

B. 2

C. 3

D. 4

A. $\frac{\mathrm{\pi }}{3}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} \mathrm{hoặc} \frac{4\mathrm{\pi }}{9}+\mathrm{k}2\frac{\mathrm{\pi }}{3}, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $\frac{\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} \mathrm{hoặc} \frac{4\mathrm{\pi }}{9}+\mathrm{k}\frac{\mathrm{\pi }}{3}, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $\frac{-\mathrm{\pi }}{3}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} \mathrm{hoặc} \frac{2\mathrm{\pi }}{9}+\mathrm{k}2\frac{\mathrm{\pi }}{3}, \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $\frac{-\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} \mathrm{hoặc} \frac{2\mathrm{\pi }}{9}+\mathrm{k}\frac{\mathrm{\pi }}{3}, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. $\pm \frac{\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc \frac{\mathrm{\pi }}{4}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $\frac{\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc \frac{\mathrm{\pi }}{4}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $-\frac{\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc \frac{\mathrm{\pi }}{4}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $\pm \frac{\mathrm{\pi }}{3}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}} hoặc \frac{\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. x = π/4+kπ, k ∈ Z

B. x = ± π/4+kπ, k ∈ Z

C. x = π/4+k2π, k ∈ Z

D. x = - π/4+kπ, k ∈ Z

A. $\frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{Z} \mathrm{hoặc} \mathrm{k}2\mathrm{\pi }, \mathrm{k}\in \mathrm{Z}$

B. $\frac{\mathrm{\pi }}{2}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{Z} \mathrm{hoặc} \mathrm{k\pi }, \mathrm{k}\in \mathrm{Z}$

C. $-\frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{Z} \mathrm{hoặc} \mathrm{k}2\mathrm{\pi }, \mathrm{k}\in \mathrm{Z}$

D. $-\frac{\mathrm{\pi }}{2}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{Z} \mathrm{hoặc} \mathrm{k\pi }, \mathrm{k}\in \mathrm{Z}$

A. x = k2π, k ∈ Z 

B. x = kπ, k ∈ Z

C. x = kπ/2, k ∈ Z

D. x = π/2+kπ, k ∈ Z

A. 0

B. π

C. 2π

D. 2π/3

A. π/2

B. 3π/2

C. π

D. 2π

A. π

B.2π

C. 3π

D. 4π

A. $\left\{-\frac{\mathrm{\pi }}{6}+k2\mathrm{\pi }, \frac{\mathrm{\pi }}{2}+\mathrm{k}2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

B. $\left\{-\frac{\mathrm{\pi }}{6}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

C. $\left\{-\frac{\mathrm{\pi }}{6}+k\mathrm{\pi }, \frac{\mathrm{\pi }}{2}+\mathrm{k\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

D. $\left\{\frac{\mathrm{\pi }}{2}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

A. $\left\{\frac{\mathrm{\pi }}{18}+k\frac{2\mathrm{\pi }}{9}, \frac{7\mathrm{\pi }}{54}+k\frac{2\mathrm{\pi }}{9}, k\in \mathrm{\mathbb{Z}}\right\}$

B. $\left\{\frac{\mathrm{\pi }}{18};\frac{7\mathrm{\pi }}{54}\right\}$

C. $\left\{\frac{\mathrm{\pi }}{18}+k\frac{2\mathrm{\pi }}{9}, \frac{-\mathrm{\pi }}{54}+k\frac{2\mathrm{\pi }}{9}, k\in \mathrm{\mathbb{Z}}\right\}$

D. $\varnothing$

A. $\left\{\pm \frac{\mathrm{\pi }}{6}+k\mathrm{\pi }, \mathrm{k\pi }; \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

B. $\left\{\pm \frac{\mathrm{\pi }}{3}+k\mathrm{\pi }; \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

C. $\left\{\pm \frac{\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k\pi }; \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

D. $\left\{\pm \frac{\mathrm{\pi }}{6}+k\mathrm{\pi }; \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

A. $\left\{\frac{\mathrm{\pi }}{3}, \mathrm{\pi }, \frac{4\mathrm{\pi }}{3}\right\}$

B. $\left\{\frac{\mathrm{\pi }}{3}, \frac{4\mathrm{\pi }}{3}\right\}$

C. $\left\{\frac{\mathrm{\pi }}{3}, \mathrm{\pi }\right\}$

D. $\left\{\frac{\mathrm{\pi }}{3}, \mathrm{\pi }, \frac{4\mathrm{\pi }}{3}, 2\mathrm{\pi }\right\}$

A. $m\ge 2 hoặc m\le -\frac{1}{2}$

B. $-2\le m\le \frac{1}{2}$

C. $-\frac{1}{2}\le m\le 2$

D. $-\frac{1}{2}<m<2$

A. $m\ge 4 hoặc m\le 0$

B. $m\ge 0 hoặc m\le -4$

C. $-4\le m\le 0$

D. $0\le m\le 4$

A. $x=\pm \frac{\mathrm{\pi }}{6}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $x=\pm \frac{2\mathrm{\pi }}{3}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $x=\mathrm{\pi }+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $x=\pm \frac{\mathrm{\pi }}{3}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. $x=\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $x=-\frac{\mathrm{\pi }}{4}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $x=\frac{-\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $x=\frac{\mathrm{\pi }}{4}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. $\mathrm{ℝ}\backslash \left\{\frac{\mathrm{\pi }}{6}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

B. $\mathrm{ℝ}\backslash \left\{\frac{\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

C. $\mathrm{ℝ}\backslash \left\{-\frac{\mathrm{\pi }}{3}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

D. $\mathrm{ℝ}\backslash \left\{\frac{\mathrm{\pi }}{3}+k\frac{\mathrm{\pi }}{2}, \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

A. $\mathrm{ℝ}$

B. $\mathrm{ℝ}\backslash \left\{\frac{\mathrm{\pi }}{12}+k\frac{\mathrm{\pi }}{3}, k\in \mathrm{\mathbb{Z}}\right\}$

C. $\mathrm{ℝ}\backslash \left\{\frac{\mathrm{k\pi }}{2}, k\in \mathrm{\mathbb{Z}}\right\}$

D. $\mathrm{ℝ}\backslash \left\{k\frac{\mathrm{\pi }}{3}, k\in \mathrm{\mathbb{Z}}\right\}$

A. $\left(0;2\mathrm{\pi }\right)\backslash \left\{\frac{\mathrm{\pi }}{2}\right\}$

B. $\left(0;2\mathrm{\pi }\right)$

C. $\left(0;2\mathrm{\pi }\right)\backslash \left\{\frac{3\mathrm{\pi }}{2}\right\}$

D. $\left(0;2\mathrm{\pi }\right)\backslash \left\{\frac{\mathrm{\pi }}{2};\mathrm{\pi };\frac{3\mathrm{\pi }}{2}\right\}$

A. y = sinx

B. y= sinx + cotx 

C. y= sin(π/2-x)

D.$y= \sin x.{\cos }^{2}x$

A. $y= {\cos }^{2}x.\cos (\pi /2-x)$

B. $y= {\sin }^{2}x\cos x$

C. y= sinx – cosx

D. y= xsinx

A. Hàm số đã cho là hàm số lẻ

B. Hàm số đã cho có giá trị lớn nhất bằng 2 

C. Hàm số đã cho có chu kì 4π 

D. Trong ba mệnh đề trên có ít nhất một mệnh đề sai

A. y= xsinx

B. y= sin3x 

C. y= x – sinx

D. y= x/(2+sinx)

A. 2π

B. 4π

C. π

D. π/2

A. 2π 

B. 5π

C. 10π

D. 2π/5

A. 2π

B. 6π

C. π/3

D. 2π/3

A. 0

B. 2π

C. 4π

D. 6π

A. 2

B. 3

C. 4

D. 6

A. 2

B. 4

C. 6

D. .8

A. sinx+ 3 = 0

B. $2{\cos }^{2}x -\cos x – 1 = 0$

C. tanx + 3 = 0

D. 3sinx – 2 = 0

A. {kπ, k∈Z}

B. {π/2+kπ,k∈Z}

C. {k2π,k∈Z}

D. Kết quả khác

A. $x=\frac{\mathrm{\pi }}{8}+k\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $x=\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $x=\frac{\mathrm{\pi }}{8}+k\frac{\mathrm{\pi }}{2}hoặc x=\frac{\mathrm{\pi }}{4}+k\mathrm{\pi } , \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $x=\frac{\mathrm{\pi }}{8}+k\mathrm{\pi } hoặc x=\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi } , \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. 3

B. 4

C. 5

D. 7

A. 1

B. 3/2

C. 2

D. Một số khác

A. 2π

B. 6π

C. 9π

D. 10π

A. x=π/4+kπ,k∈Z

B. x=π/4+k π/2,k∈Z

C. x=π/2+kπ,k∈Z

D. x=0

A. {π/2+k2π,k∈Z}

B. {π/6+k2π,k∈Z}

C. {π/6+k π/3,k∈Z}

D. {π/6+k2 π/3,k∈Z}

A. {k2π,k∈Z}

B. {π/4+k2π,k∈Z}

C. {±π/4+k2π,k∈Z}

D. ∅

A. $4{\sin }^{2}x – 5\sin x\cos x -{\cos }^{2}x = 0$

B. $4{\sin }^{2}x + 5\sin x\cos x + {\cos }^{2}x = 0$

C. $4{\tan }^{2}x – 5\tan x + 1 =0$

D. $5\sin 2x + 3\cos 2x = 2$

A. {π/6+kπ,k∈Z}

B. {π/2+kπ,k∈Z}

C. {π/6+kπ,π/2+kπ,k∈Z}

D. {π/2+k2π,k∈Z}

A. {k2π,π/2+k2π;k∈Z}

B. {kπ,π/2+k2π;k∈Z}

C. {π/2+k2π;k∈Z}

D. ∅

A. {-π/2+k2π;k∈Z}

B. {π/2+kπ;k∈Z}

C. {k2π;k∈Z}

D. ∅

A. – 1/2 và 2

B. 1/2 và 2

C. -2 và -1/2

D. -2 và 1/2

A. 5

B. $3 +\sqrt{2}$

C.$3 - \sqrt{2}$

D. 3

A. ℝ\{kπ,k∈Z}

B. ℝ\{k2π,k∈Z}

C. ℝ\{π/2+kπ,k∈Z}

D. ℝ\{π/4+kπ,k∈Z}

A. 0

B. 2π

C. 4π

D. 6π

A. $y = x^2. cosx$

B. y = sin2x

C. $y = {\sin }^{2}x$

D. y = cosx

A. ℝ\{x│sin2x < 0}

B. ℝ\{k2π,k∈Z}

C. ℝ

D. Một tập hợp khác

A. m ≥ 2

B. m ≤ 2

C. m ≥ 4

D. m ≤ 4

A. x= π/2

B. x = π/4

C. x = -π/2

D. x = 2π/3

A. 0

B. -2

C. 5

D. -1

A. 1/2 và 1

B. 1/2 và 2

C. 2/11 và 1

D. 2/11 và 2

A. {-π/2+kπ,k∈Z}

B. {-π/2+k2π,k∈Z}

C. {-π/6+k2π,k∈Z}

D. {-π/6+k 2π/3,k∈Z}

A. {-π/4+kπ,k∈Z}

B. {π/4+kπ,k∈Z}

C. {±π/4+k2π,k∈Z}

D. ∅

A. ℝ

B. $ℝ\backslash \{\pi /4+k\pi /2,k\in Z\}$

C. $ℝ\backslash \{\pi /2+k\pi ,k\in Z\}$

D. $\varnothing$

A. {π/4+kπ,kπ,k∈Z}

B. {kπ,k∈Z}

C. {π/4+k2π,k∈Z}

D. {k2π,k∈Z}

A. {0,π/5}

B. {2π/5,4π/5}

C. {π/5,2π/5}

D. {2π/5,3π/5,4π/5}

A. $y = \cos \frac{2x}{3}$

B. $y = \sin \frac{2x}{3}$

C. $y =cos\frac{3x}{2}$

D. $y = \sin \frac{3x}{2}$

A. {π/12+kπ,k∈Z}

B. {1/12+k,k∈Z}

C. {π/2+kπ,k∈Z}

D. {1/2+kπ,k∈Z}

A. $x=-\frac{\mathrm{\pi }}{4}+k\mathrm{\pi } \mathrm{hoặc} \mathrm{x}=\frac{\mathrm{\pi }}{2}+\mathrm{k\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

B. $x=\frac{\mathrm{\pi }}{4}+k\mathrm{\pi } \mathrm{hoặc} \mathrm{x}=\frac{\mathrm{\pi }}{2}+\mathrm{k\pi }, \mathrm{k}\in \mathrm{\mathbb{Z}}$

C. $x=-\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi } \mathrm{hoặc} \mathrm{x}=\frac{\mathrm{\pi }}{2}+k2\pi , \mathrm{k}\in \mathrm{\mathbb{Z}}$

D. $x=\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi } \mathrm{hoặc} \mathrm{x}=\frac{\mathrm{\pi }}{2}+k2\pi , \mathrm{k}\in \mathrm{\mathbb{Z}}$

A. $\left\{-\frac{\mathrm{\pi }}{4}+k\mathrm{\pi }, \mathrm{k}\frac{\mathrm{\pi }}{2}; \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

B. $\left\{-\frac{\mathrm{\pi }}{4}+k2\mathrm{\pi }, \mathrm{k\pi }; \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

C. $\left\{-\frac{\mathrm{\pi }}{4}+k\mathrm{\pi }; \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

D. $\left\{\mathrm{k}\frac{\mathrm{\pi }}{2}; \mathrm{k}\in \mathrm{\mathbb{Z}}\right\}$

A. 3sinx + 1 = 0

B. $2{\cos }^{2}x – \cos x -1 = 0$

C. 5tanx + 3 = 0

D. 3cosx – 5 = 0

A. R

B. R\{0}

C. [0;+∞)

D. (0;- ∞)