Re: [中學] 三角函數 內切圓
※ 引述《justin0602 (justin)》之銘言：
: http://picmoe.net/d.php?id=1356754275908
連 AI IB ID 看直角三角形 ADI 及 BDI
易知 sin(A/2) = 1/√10 sin(B/2) = 1/√17
cos(A/2) = 3/√10 cos(B/2) = 4/√17
於是 sin A = 3/5 sin B = 8/17
sin C = sin(π-A-B) = sin(A+B)
= sin A cos B + cos A sin B
= (3/5)(15/17) + (4/5)(8/17) = 77/85
--
LPH [acronym]
= Let Program Heal us
-- New Uncyclopedian Dictionary, Minmei Publishing Co.
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 180.218.108.125
推
12/29 12:33, , 1F
12/29 12:33, 1F
討論串 (同標題文章)