Vì \(\pi< \alpha< \dfrac{3\pi}{2}\) \(\Rightarrow\dfrac{\pi}{2}< \dfrac{\alpha}{2}< \dfrac{3\pi}{4}\)

\(\Rightarrow sin\dfrac{\alpha}{2}>0;cos\dfrac{\alpha}{2}< 0\)

\(\pi< \alpha< \dfrac{3\pi}{2}\Rightarrow cos\alpha< 0\)

\(\Rightarrow cos\alpha=-\sqrt{1-sin^2\alpha}=-\dfrac{3}{5}\)

Có \(sin^2\dfrac{\alpha}{2}=\dfrac{1-cosa}{2}=\dfrac{4}{5}\Rightarrow sin\dfrac{\alpha}{2}=\sqrt{\dfrac{4}{5}}=\dfrac{2\sqrt{5}}{5}\)

\(cos^2\dfrac{\alpha}{2}=\dfrac{1+cosa}{2}=\dfrac{1}{5}\Rightarrow cos\dfrac{\alpha}{2}=-\sqrt{\dfrac{1}{5}}=-\dfrac{\sqrt{5}}{5}\)

\(tan\dfrac{\alpha}{2}=\dfrac{sin\dfrac{\alpha}{2}}{cos\dfrac{\alpha}{2}}=-2\)

\(cot\dfrac{\alpha}{2}=-\dfrac{1}{2}\)

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41436 nha

      3 x 4 x 45 + 12 x 25 + 12 x 3

= 12 x 45 + 12 x 25 + 12 x 3

= 12 x (45 + 25 + 3)

= 12 x 73

= 876

Bạn chắc chứ

\(\frac{3}{4}m=0,75cm\)

x/-30+1,75=-5/9:4/3

=>x/-30+7/4=-5/12

=>x/-30=-13/6

=>x.6=-30.-13

=>x.6=390

=>x=65

vậy x=65.

bạn viết rõ ra phân số ra nha!

Độ lớn lực hấp dẫn:

\(F_{hd}=G\cdot\dfrac{M\cdot m}{\left(R+h\right)^2}=6,67\cdot10^{-11}\cdot\dfrac{6\cdot10^{24}\cdot2,7\cdot10^3}{\left(6400\cdot1000+35798\right)^2}=26087,71N\)

câu j vậy bn

bạn giúp mình bài 7 trang 10 toán 7 ki 1 nhé

bạn có sdt ko cho mình xin với

 ngu

ngu thế