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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 11: cos(2x+pi/4)=-1/3 Giải giúp mình với

Tháng Một 6, 2023 Toán học 2 Comments 0 views

Toán Lớp 11: cos(2x+pi/4)=-1/3
Giải giúp mình với

Comments ( 2 )

  1. cobebongdem
    cobebongdem
    6 Tháng Một, 2023 at 7:49 chiều
    Reply
    cos(2x+π/4)=-1/3
    ⇔  \(\left[ \begin{array}{l}2x+π/4=arccos(-1/3) + k2π\\2x+π/4=-arccos(-1/3) + k2π\end{array} \right.\) 
    ⇔ $\left[\begin{matrix} 2x=-π/4+arccos(-1/3) + k2π\\ 2x=-π/4-arccos(-1/3) + k2π\end{matrix}\right.$
    ⇔ $\left[\begin{matrix} x=-π/8+1/2arccos(-1/3) + kπ\\ x=-π/8-1/2arccos(-1/3) + kπ\end{matrix}\right.$
    Vậy….
     

  2. kimnguenoanh
    kimnguenoanh
    6 Tháng Một, 2023 at 7:48 chiều
    Reply
    $cos(2x+\dfrac{\pi}{4}=\dfrac{-1}{3}$
    $⇔$\(\left[ \begin{array}{l}2x+\dfrac{\pi}{4}=arccos(\dfrac{-1}{3})+k2\pi\\2x+\dfrac{\pi}{4}=-arccos(\dfrac{-1}{3})+k2\pi\end{array} \right.\) 
    $⇔$\(\left[ \begin{array}{l}2x=-\dfrac{\pi}{4}+arccos(\dfrac{-1}{3})+k2\pi\\2x=-\dfrac{\pi}{4}-arccos(\dfrac{-1}{3})+k2\pi\end{array} \right.\) 
    $⇔$\(\left[ \begin{array}{l}x=-\dfrac{\pi}{8}+\dfrac{1}{2}arccos(\dfrac{-1}{3})+k\pi\\x=-\dfrac{\pi}{8}-\dfrac{1}{2}arccos(\dfrac{-1}{3})+k\pi\end{array} \right.\) 

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222-9+11+12:2*14+14 = ? ( )

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