Question

COS 50 ГРАДУСОВ+SIN 160 ГРАДУСОВ- COS 10 ГРАДУСОВ


ХЕЛП МИ, ПИПЛС

Answer 1

cos(a)-cos(b) = -2*sin( (a+b)/2) *sin( (a-b)/2)
cos 50- cos 10 = -2*sin(30)*sin(20)
sin(30) = 1/2
cos(50)-cos(10) = -sin(20)
sin(a)-sin(b) = 2*sin[(a-b)/2]*cos[(a+b)/2]
sin(160)-sin(20) = 2*sin(70)*cos(90) = 0