Cosx + 5 sin x/2 – 3=0

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Cosx + 5 sin x/2 – 3=0

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Ladonna 4 years 2020-11-13T19:36:28+00:00 2 Answers 60 views 0

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  1. Ladonna
    0
    2020-11-13T19:37:58+00:00
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    Đáp án:

     

    Giải thích các bước giải:

     khen tuii đi~~

    cos-5-sin-2-3-0

  2. Vodka
    0
    2020-11-13T19:38:11+00:00
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    Giải thích các bước giải:

    $\cos{x} + 5\sin{\dfrac{x}{2}} – 3 = 0$

    $\Leftrightarrow 1 – 2\sin^{2}{\dfrac{x}{2}} + 5\sin{\dfrac{x}{2}} – 3 = 0$

    $\Leftrightarrow 2\sin^{2}{\dfrac{x}{2}} – 5\sin{\dfrac{x}{2}} + 2 = 0$

    $\Leftrightarrow \left[ \begin{array}{l}\sin{\dfrac{x}{2}} = \dfrac{1}{2}\\\sin{\dfrac{x}{2}} = 2 (L)\end{array} \right.$

    $\Leftrightarrow \sin{\dfrac{x}{2}} = \sin{\dfrac{\pi}{6}}$

    $\Leftrightarrow \left[ \begin{array}{l}\dfrac{x}{2} = \dfrac{\pi}{6} + k2\pi\\\dfrac{x}{2} = \dfrac{5\pi}{6} + k2\pi\end{array} \right.$

    $\Leftrightarrow \left[ \begin{array}{l}x = \dfrac{\pi}{3} + k4\pi\\x = \dfrac{5\pi}{3} + k4\pi\end{array} \right.$

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )