Cos(75) = 1/4*(√6-√2)

cos75=0.259 或者 cos75=cos(30+45)=cos30cos45-sin30sin45=√6/4-√2/4=(√6-√2)/4

cos75=cos(45+30)=cos45cos30-sin45sin30=(√2/2)(√3/2-1/2)=(√6-√2)/4

sin75°=sin(45°+30°)=sin45°cos30°+cos45°sin30°=(√6+√2)/4 cos75=cos(30+45)=cos30cos45-sin30sin45=√6/4-√2/4=(√6-√2)/4 sin75+cos75=sin75+sin15=2sin(75+15)/2cos(75-15)/2=2sin45cos30=√6/2 sin75-cos75=sin75-sin15=2cos(

把他换成cos(30°+45°)就好算了,用公式就行了cos30°cos45°-sin30°sin45°=(根号6-根号2)/4结果等于4分之(根号6减根号2)要想换成小数就是cos(75°) = 0.25881904510252076234889883762405自己看着需要吧!

cos75°=cos(30°+45°)=cos30°cos45°-sin30°sin45°=(√6-√2)/4 cos135°=cos(90°+45°)=-cos45°=-√2/2

cos75度=0.258819;sin75度=0.965926

cos75°=sin15°=sin(45°-30°)=sin45°cos30°-sin30°cos45°=(√6-√2)/4

cos75=(根号6-根号2)/4