cos15度的值等于多少

2025-04-13 14:18:07
推荐回答(1个)
回答1:

2[cos15°]^2 -1 = cos30°
2[cos15°]^2 -1 = √3/2
[cos15°]^2 = (2+√3)/4
cos15° =(1/2)√(2+√3)
=(1/4)(√2+√6)