sin75度+cos15度=————————————

问题描述:

sin75度+cos15度=————————————

原式=2cos15°=2cos(45°-30°)=2(cos45°cos30°+sin45°sin30°)
=2(√2/2•√3/2+√2/2•1/2)
剩下的就自己算吧!!

sin75°+cos15°
=sin75°+sin75°
=2sin75°
=2sin(45°+30°)
=2[(√2/2)(√3/2)+(√2/2)(1/2)]
=(√6+√2)/2