от Nathi123 » 28 Дек 2016, 19:24
A=[tex]\frac{1}{1-cos\alpha}+\frac{1}{1+cos\alpha} = \frac{2}{1-cos^{2}\alpha}=\frac{2}{sin^{2}\alpha}[/tex]
[tex]sin(2007\pi -\alpha)=sin(1003.2\pi +\pi - \alpha ) = sin( \pi - \alpha )=sin\alpha \Rightarrow sin\alpha = 0,25\Rightarrow A = \frac{2}{0,0625}=32[/tex].