Question

Sa se calculeze sin 105; cos75

Answer 1

Sin105=V2(1+V3)/4

Cos75=V2(V3-1)/4

Unde V2=rad(2), V3=rad(3)

105=60+45

Sin105=sin(60+45)=sin60 cos45+sin45 cos60=

V3/2×V2/2+V2/2×1/2=V2(1+V3)/4

75=30+45

Cos75=cos(30+45)=cos30 cos45-sin30 sin45=

V3/2×V2/2-1/2×V2/2=V2(V3-1)/4