от Nathi123 » 04 Ное 2016, 19:27
[tex]4(1+cosx)sin^{2}\frac{x}{2} = 3sinx +2 \Leftrightarrow 4(1 + cosx)\frac{1-cosx}{2} = 3sinx +2[/tex]
[tex]\Leftrightarrow 2(1 + cosx)( 1 - cosx) = 3sinx +2\Leftrightarrow 2(1-cos^{2}x) = 3sinx +2\Leftrightarrow 2sin^{2}x - 3sinx -2 =0[/tex]
[tex]\Rightarrow sinx=2[/tex] - няма реални корени [tex]( |sinx|\le 1) \cup sinx = -\frac{1}{2}\Leftrightarrow x = - \frac{\pi}{6}+2k\pi \cup x=\pi+ \frac{\pi}{6}+2k\pi ; k\in Z[/tex] .