Salut,
[tex]\dfrac{2cos\left(\dfrac{\pi}2-x\right)\cdot sin\left(\dfrac{\pi}2-x\right)\cdot tg\left(\pi-x\right)}{ctg\left(\dfrac{\pi}2+x\right)\cdot sin(\pi-x)\cdot cos(2\pi-x)}=\dfrac{2sin x\cdot cosx\cdot(-tgx)}{(-tgx)\cdot sinx\cdot cos(-x)}=\\\\=\dfrac{2sin x\cdot cosx\cdot(-tgx)}{(-tgx)\cdot sinx\cdot cosx}=2.[/tex]
Green eyes.