Найдите решение тригоном.неравенства: 1) 2sin^2(x+3п/2)≥1/2 3п/2-дробь 2)ctg3x-√3≥0

Ответы

mrmersbrady 02.10.2020 17:46

$2\sin^2(x+ \cfrac{3 \pi }{2}) \geq \cfrac{1}{2} 
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\sin^2(x+ \cfrac{3 \pi }{2}) \geq \cfrac{1}{4} 
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\left[ \begin{matrix} \sin(x+ \cfrac{3 \pi }{2}) \geq \cfrac{1}{2} \\ \sin(x+ \cfrac{3 \pi }{2}) \leq -\cfrac{1}{2} \end{array}\right.
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\left[ \begin{matrix} \cfrac{ \pi }{6}+2 \pi k \leq x+ \cfrac{3 \pi }{2} \leq \cfrac{ 5\pi }{6}+2 \pi k \\ - \cfrac{5 \pi }{6}+2 \pi n \leq x+ \cfrac{3 \pi }{2} \leq -\cfrac{ \pi }{6}+2 \pi n \end{array}\right.$
$\left[ \begin{matrix} \cfrac{ \pi }{6}- \cfrac{3 \pi }{2}+2 \pi k \leq x \leq \cfrac{ 5\pi }{6}- \cfrac{3 \pi }{2}+2 \pi k \\ - \cfrac{5 \pi }{6}- \cfrac{3 \pi }{2}+2 \pi n \leq x \leq -\cfrac{ \pi }{6}- \cfrac{3 \pi }{2}+2 \pi n \end{array}\right.
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\left[ \begin{matrix} - \cfrac{4 \pi }{3}+2 \pi k \leq x \leq -\cfrac{ 2\pi }{3}+2 \pi k, \ k\in Z \\ - \cfrac{7 \pi }{3}+2 \pi n \leq x \leq- \cfrac{5 \pi }{3}+2 \pi n, \ n\in Z \end{array}\right.$

$\mathrm{ctg}3x- \sqrt{3} \geq 0 
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\mathrm{ctg}3x \geq \sqrt{3}
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\pi n\ \textless \ 3x \leq \cfrac{ \pi }{6}+ \pi n
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 \cfrac{\pi n}{3} \ \textless \ x \leq \cfrac{ \pi }{18}+ \cfrac{\pi n}{3}, \ n\in Z$