Xin các thầy cô giúp
Ta có : [tex]P=\frac{U^2.cos(\varphi)^2}{R}[/tex]
[tex]P_{max}=\frac{U^2}{2R}[/tex]
[tex]==> GT P=P_{max}/2 ==> cos(\varphi)=\frac{\sqrt{2}}{2} ==> |ZL-ZC|=R[/tex]
[tex]Th1 : ZL-ZC=R ==> LC\omega^2-1=R.C\omega [/tex]
[tex]==> 10^{-5}\omega^2-\frac{1}{200\pi}.\omega -1=0 ==> \omega=1630rad/s[/tex]
[tex]Th2 : ZL-ZC=-R ==> LC\omega^2-1=-R.C\omega [/tex]
[tex]==> 10^{-5}\omega^2+\frac{1}{200\pi}.\omega -1=0 ==> \omega=61,3rad/s[/tex]