1) http://dientuvietnam.net/cgi-bin/mimetex.cgi?\dfrac{1}{cosxcos2x}+\dfrac{1}{cos2xcos3x}+\dfrac{1}{cos3cos4x}+\dfrac{1}{cos4xcos5x}=0
3) http://dientuvietnam.net/cgi-bin/mimetex.cgi?\dfrac{cos5x}{cosx}+\dfrac{cos10x}{cos2x}+\dfrac{cos20x}{cos4x}=3
4) http://dientuvietnam.net/cgi-bin/mimetex.cgi?\dfrac{sin5x}{sinx}=2cosx+\dfrac{3}{2}
Bài viết đã được chỉnh sửa nội dung bởi hoacomay: 18-06-2005 - 07:10
