×

ANNIE

證明的題目

想了很久也想不出,求指教!!

附加文件

解答 0

  • eric
    2020-01-03 22:18:15
    Let A=∠KAP, A'=∠BAC, B=∠HBN, B'=∠ABC, C=∠QCM, C'=ACB
  • eric
    2020-01-03 22:20:52
    Then x^2=b^2+c^2-2bccosA, y^2=a^2+c^2-2accosB, z=a^2+b^2-2abcosC
  • eric
    2020-01-03 22:25:20
    Now try to prove yourself that x^2=b^2+c^2+2bccosA=2b^2+2c^2-a^2
  • eric
    2020-01-03 22:26:38
    Do the same for y^2 and z^2
  • eric
    2020-01-03 22:27:35
    Adding the three equalities together, you will get the desired result
  • eric
    2020-01-03 22:28:34
    Correction: Now try to prove yourself that x^2=b^2+c^2+2bccosA'=2b^2+2c^2-a^2
    •  eric 2020-01-03 22:25:20
    • Now try to prove yourself that x^2=b^2+c^2+2bccosA=2b^2+2c^2-a^2
  • eric
    2020-01-03 22:32:50
    Correction: Then x^2=b^2+c^2-2bccosA, y^2=a^2+c^2-2accosB, z^2=a^2+b^2-2abcosC
    •  eric 2020-01-03 22:20:52
    • Then x^2=b^2+c^2-2bccosA, y^2=a^2+c^2-2accosB, z=a^2+b^2-2abcosC
  • eric
    2020-01-03 22:34:10
    Correction: Let A=∠KAP, A'=∠BAC, B=∠HBN, B'=∠ABC, C=∠QCM, C'=∠ACB
    •  eric 2020-01-03 22:18:15
    • Let A=∠KAP, A'=∠BAC, B=∠HBN, B'=∠ABC, C=∠QCM, C'=ACB
  • ANNIE
    2020-01-04 00:52:59
    Thanks!
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)