×

student2280

求step或解釋 Prove q.

附加文件

解答 0

  • eric
    2019-05-22 20:54:49
    21. Proof is given in https://zhidao.baidu.com/question/53815592.html
  • eric
    2019-05-22 20:59:06
    25a. Use sin(90°-θ)=cosθ
  • student2280
    2019-05-22 21:34:03
    Thanks
  • tayh
    2019-05-23 00:46:10
    25(b) y= sin20sin40sin80*(sin60) =-1/2(cos60-cos20)sin80*(根号3/2) =-1/2(1/2-cos20)sin80*(根号3/2) =-1/4*sin80+1/2*[cos20 sin80]*(根号3/2) =-1/4*sin80+1/2*[1/2*(sin60+sin100)]*根号3/2 =(-1/4*sin80+1/4*sin60+1/4*sin100)*根号3/2 =(-1/4*sin80+1/4*sin60-1/4*sin80)*根号3/2 =1/4*根号3/2*根号3/2 =3/16 so, y sin 10 = 3/16 sin 10 = 3/16 sin 80

    附加文件

  • tayh
    2019-05-23 00:49:47
    更正 25(b) y= sin20sin40sin80*(sin60) =-1/2(cos60-cos20)sin80*(根号3/2) =-1/2(1/2-cos20)sin80*(根号3/2) =-1/4*sin80+1/2*[cos20 sin80]*(根号3/2) =-1/4*sin80+1/2*[1/2*(sin60+sin100)]*根号3/2 =(-1/4*sin80+1/4*sin60+1/4*sin100)*根号3/2 =(-1/4*sin80+1/4*sin60+1/4*sin80)*根号3/2 =1/4*根号3/2*根号3/2 =3/16 so, y sin 10 = 3/16 sin 10 = 3/16 sin 80

    附加文件

請填寫內容
解答內容包含禁止的詞
請輸入你的答案
上載文件更改 ×
檔案過大
不支援此檔案
jpg, gif, png, doc, docx, pdf, xls, mov, mp4, m4a, mp3 (檔案上限為50M)