链接列表

艾伦英语 https://www.ixigua.com/home/52188846944/?source=pgc_author_name&list_entrance=anyVideo
英语 https://www.ixigua.com/7048219453275767310?logTag=4aa85a1b10acb22900ad
高考试题https://xw.qq.com/amphtml/20220608A0B44S00
公园有一个菜地 http://www.1010jiajiao.com/gzsx/shiti_id_86ca931bb0a03ae4dc45f4c9b6081b12
卫星进入轨道http://www.1010jiajiao.com/gzwl/shiti_id_9944d0cf9615ea6448c838069e030662
求证：cosA+cosB+cosC=1+4sinA/2sinB/2sinC/2
https://zhidao.baidu.com/question/62568974.html
cosA+cosB+cosC=2cos(A-B)/2cos(A+B)/2+cosC
=2cos(A-B)/2sin(π-A-B)/2+1-2sin^2(C/2)
=2cos(A-B)/2sinC/2+1-2sin^2(C/2)
=2sinC/2(cos(A-B)/2-sinC/2)+1
=2sinC/2(cos(A-B)/2-cos（A+B)/2)+1
=sinC/22sinA/2sinB/2+1
=1+4sinA/2sinB/2sinC/2
好难打啊，可累死我了，上大学还得做高中的题，呼呼`千万给我分哦~
核心词汇https://www.ixigua.com/6998598287456469534
歌曲https://haokan.baidu.com/v?vid=8546057907546686331&tab=
歌曲https://haokan.baidu.com/v?vid=6805964237516564360
三月里的小雨 https://haokan.baidu.com/v?vid=17902681524889333601
梁红https://haokan.baidu.com/v?vid=8413176522459695449&tab=
三月里的小雨https://haokan.baidu.com/v?vid=17902681524889333601