D
dungkute1995


Với [TEX]x,y \in(0;9^o)[/TEX]
[TEX]A= \frac{cos^2x}{1-cosx}+\frac{cos^2y}{1-cosy}+\frac{1}{cosx+cosy}+cosx+cosy[/TEX]
[TEX]A= \frac{cos^2x}{1-cosx}+\frac{cos^2y}{1-cosy}+\frac{1}{cosx+cosy}+cosx+cosy[/TEX]
Last edited by a moderator: