A) sin15°*cos15°=1/2(sin(15°-15°)+sin(15°+15°))=1/2(sin0°+sin30°)=
=1/2(0+1/2)=1/2*1/2=1/4=0,25;
b) sin²27°+cos²27°=1;
c) sin²46°+sin²44°=sin²46°+sin²(90°-46°)=sin²46°+cos²46°=1;
d) cos²15°-sin²15°=cos(2*15°)=cos30°=√3/2;
e) cos15°(cos50°*sin65°-cos65°*sin50°)=cos15°*sin(65°-50°)=cos15°*sin15°=
=1/2*2cos15°*sin15°=1/2*sin(2*15°)=1/2*sin30°=1/2*1/2=1/4=0,25;
=1/2(0+1/2)=1/2*1/2=1/4=0,25;
b) sin²27°+cos²27°=1;
c) sin²46°+sin²44°=sin²46°+sin²(90°-46°)=sin²46°+cos²46°=1;
d) cos²15°-sin²15°=cos(2*15°)=cos30°=√3/2;
e) cos15°(cos50°*sin65°-cos65°*sin50°)=cos15°*sin(65°-50°)=cos15°*sin15°=
=1/2*2cos15°*sin15°=1/2*sin(2*15°)=1/2*sin30°=1/2*1/2=1/4=0,25;