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

Toán Lớp 11: cot($\frac{\pi}{2}$-3x)=0 cot(x+2)=3 cot(x-$\frac{\pi}{6}$)=$\frac{1}{\sqrt[]{3}}$ cot($\frac{x}{2}$-$\frac{\pi}{4}$)=1

Toán Lớp 11: cot($\frac{\pi}{2}$-3x)=0
cot(x+2)=3
cot(x-$\frac{\pi}{6}$)=$\frac{1}{\sqrt[]{3}}$
cot($\frac{x}{2}$-$\frac{\pi}{4}$)=1

Comments ( 1 )

  1. $cot(\dfrac{\pi}{2}-3x)=0$
    Điều kiện $sinx\ne0$
    $⇔x\ne k\pi$
    $⇔\dfrac{\pi}{2}-3x=\dfrac{\pi}{2}+k\pi$
    $⇔x=k3\pi(k∈Z)(l)$
    $cot(x+2)=3$
    Điều kiện $sin(x+2)\ne0$
    $⇔x+2\ne k\pi$
    $⇔x\ne-2+ k\pi$
    $⇔x+2=arccot(3)+k\pi$
    $⇔x=-2+arccot(3)+k\pi$
    $cot(x-\dfrac{\pi}{6})=\dfrac{1}{\sqrt[]{3}}=cot(\dfrac{\pi}{3})$
    Điều kiện $sin(x-\dfrac{\pi}{6})\ne0$
    $⇔x-\dfrac{\pi}{6}\ne k\pi$
    $⇔x\ne \dfrac{\pi}{6}+k\pi$
    $⇔x-\dfrac{\pi}{6}=\dfrac{\pi}{3}+k\pi$
    $⇔x=\dfrac{\pi}{2}+k\pi(k∈Z)$

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