2sin 60°+cos90°- tg45°

[latex]2sin 60+cos90- tg45=2sin60cos60+cos90-tg45= \\ =2 \frac{ \sqrt{3} }{2} * \frac{1}{2} +0-1=\frac{ \sqrt{3} }{2}}-1=\frac{ \sqrt{3} -2}{2}[/latex]