cosa+ cos180-a⼀2等于多少怎么算

2025-06-27 16:07:18
推荐回答(1个)
回答1:

cosa+ cos180-a/2
=cosa-cosa/2
=2cos²(a/2)-1-cos(a/2)‍
=2[cos(a/2)-1/4]²-9/8