1.
[tex]DK:sin(x+\frac{\pi}{3})sin(\frac{\pi}{6}-3x)\neq 0\Leftrightarrow ...\\PT\Leftrightarrow \frac{cos(x+\frac{\pi}{3})sin(\frac{\pi}{6}-3x)+sin(x+\frac{\pi}{3})cos(\frac{\pi}{6}-3x)}{sin(x+\frac{\pi}{3})sin(\frac{\pi}{6}-3x)}=0\\\Leftrightarrow \frac{sin(x+\frac{\pi}{3}+\frac{\pi}{6}-3x)}{sin(x+\frac{\pi}{3})sin(\frac{\pi}{6}-3x)}=0\\\Leftrightarrow sin(\frac{\pi}{2}-2x)=0\\\Leftrightarrow cos2x=0\\\Leftrightarrow ...[/tex]
2. Đề yêu cầu gì mà có m thế bạn
3.
[tex]DK:cosxcos4x\neq 0\Leftrightarrow ...\\PT\Leftrightarrow sinxsin4x=-cosxcos4x\\\Leftrightarrow cosxcos4x+sinxsin4x=0\\\Leftrightarrow cos3x=0\\\Leftrightarrow ...[/tex]
[TẶNG BẠN] TRỌN BỘ Bí kíp học tốt 08 môn
