1. $8cos4x.cos^{2}2x + \sqrt{1-cos3x}+1=0$
2. $2sin^{2}x+2\sqrt{3}sinxcosx+1=3(cosx+\sqrt{3}sinx)$
3. $16cos^{4}(x+\frac{\pi }{4})=4\frac{1-tan^{2}x}{1+tan^{2}x}-2sin4x$
4. $sin4x+2=cos3x+4sinx+cosx$
5. $4sinx.sin\left ( \frac{\pi}{3}+x \right ).sin\left ( \frac{\pi }{3}-x \right )-4\sqrt{3}cosx.cos\left ( \frac{\pi }{3}+x\right ).cos\left ( \frac{2\pi }{3}+x \right )=2$
6.$5cos3\left ( x+\frac{\pi }{6} \right )+3cos5\left ( x-\frac{\pi }{10} \right )=0$
7.$cos^{3}x.cos3x+sin^{3}x.sin3x=\frac{\sqrt{2}}{4}$
8.$4^{sinx}-2^{1+sinx}.cos(xy)+2^{\left | y \right |}=0$
Bài viết đã được chỉnh sửa nội dung bởi chelsea112013: 29-04-2013 - 11:01