Корень из 3 cos 7п/6 + cos(-480)

Question

Корень из 3 cos 7п/6 + cos(-480)

Answer 1

√3.cos(7π/6)+cos(-480°)=√3.cos(210°)+cos(480°)=
=√3.cos(180°+30°)+cos(360°+120°)=√3.(-cos30°)+cos120°=
=√3.(-√3/2)-cos60°=-3/2-1/2=-4/2=-2

Comments

Отдуши душевно в душу.