👤

Ma puteti ajuta sa rezolv: sin10+sin20+sin170+sin180? Multumesc anticipat

Răspuns :

sin 170=sin(180-10)=sin180*cos10-sin10*cos180=sin10
sin180=0
sin20=sin 2*10=2sin10*cos10
sin10+sin20+sin170+sin180=
=sin10+2sin10cos10+sin10=
=2sin10+2sin10cos10=
=2sin10(1+cos10)