Question

Вычислите:

sin 11pi/12+sin 5pi/12

Answer 1

sin2a=2siacosa.
sin(2*11pi/6)+sin(2*5pi/6)=
=2sin11pi/6cos11pi/6+
+2sin5pi/6cos5pi/6=
=(2*(-1/2)*√3/2)+
(2*1/2*(-√3/2))=
-√3/2-√3/2=-√3