15度,30度,45度,60度,75度,90度,105度,120度,135度,150度,180度,270...答:sin15=sin(60-45)=sin60cos45-cos60sin45=(根号6 可以设∠A=∠B+∠C sinA=sin(B+C)=sinBcosC+cosBsinC cosA=cos(B+C)=cosBcosC-sinBsinC tanA=tan(B+C)=(tanB+tanC)/(1-tanBtanC)角度0° 30° 45° 60° 90° sin 0 1/2 √2/2 √3/2 1 cos 1...
15度,30度,45度,60度,75度,90度,105度,120度,135度,180度,270度,360...答:30 45 60 75 90 sin 1/2 √2/2 √3/2 √2/2 1 cos √3/2 √2/2 1/2 (√6-√2)/4 0 tan √3/3 1 √3 -√3/8-1/2 不存在