Câu hỏi
Nghiệm của phương trình cos3x – 4sin3x – 3cosx.sin2x + sinx = 0 là:
A
\(x = -\frac{\pi}{4} + k\pi, x = \frac{\pi}{6} + k\pi, x = -\frac{\pi}{6} + k\pi, k \in \mathbb{Z}\)
B
\(x = \frac{\pi}{4} + k\pi, x = \frac{\pi}{6} + k\pi, x = -\frac{\pi}{6} + k\pi, k \in \mathbb{Z}\)
C
\(x = -\frac{\pi}{4} + k\pi, x = \frac{\pi}{6} + k\pi, x = \frac{5\pi}{6} + k\pi, k \in \mathbb{Z}\)
D
\(x = -\frac{3\pi}{4} + k\pi, x = \frac{\pi}{6} + k\pi, x = -\frac{\pi}{6} + k\pi, k \in \mathbb{Z}\)