Question

Спростити вираз
sin(90°-а) - cos(180°-а) - ctg(270°+a).​

Answer 1

$\displaystyle\bf\\Sin(90^\circ-\alpha )-Cos(180^\circ-\alpha )-Ctg(270^\circ +\alpha )=\\\\=Cos\alpha -Cos\alpha +tg\alpha =tg\alpha$