卓卓 asked in 科學及數學數學 · 7 years ago

數學補習題目(續三角)一問

請解答下列網址的第五題(Q5.): [第一步驟如何去到第二步驟]

https://docs.google.com/document/d/1GYPN1AVRrmbpyr...

1 Answer

Rating
  • Ka ho
    Lv 5
    7 years ago
    Favorite Answer

    cos(x+340) √ [ 1/cos^2 (x+340) - 1] = 1/2

    √[ cos^2 (x+340) ] * √ [ 1/cos^2 (x+340) -1 ] = 1/2

    √ [ 1 - cos^2 (x+340) ] = 1/2

    √ [ sin^2 (x+340) ] = 1/2

    ±sin (x+340) = 1/2

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