Question

a)Sin49 grade cos 11 grade+cos 49 grade sin 11 grade
b)Sin 57 grade cos 12 grade-cos 57 grade sin 12 grade
c)cos 85 grade cos 35 grade-sin 85 grade sin 35 grade
d)cos 109 grade cos 49 grade+sin 109 grade sin 49 grade

Answer 1

Răspuns:

√3/2

√2/2

-1/2

1/2

Explicație pas cu pas:

aplicam formule pt sinuisul si cosinusul sumelor/diferentelor de unghiuri

a) sin(49+11)°=sin60°=√3/2

b)sin(57-12)°=sin45°=√2/2

c)cos(85+35)°=cos120°=-cos60°=-1/2

cos(109-49)°=cos60°=1/2