Question

cos180 - 2tg (-45) + 4sin 390

Answer 1

cos 180° -2.tg (-45°) + 4.sin 390°=
= -1 -2.(-1) +4.sin(360°+30°)=-1+2+4.sin30°=1+4.1/2=
=1+2=3

cos 180°=-1
tg(-45°)=-tg45°=-1
sin 390°=sin 30°=1/2