Good Day All;

Could someone help me in this question?

Calculate the resonant frequency of the circuit in Figure in the attachment.

 

Hello,

Take a look at this page from our eBook:
http://www.allaboutcircuits.com/vol_2/chpt_6/5.html

Bertus

 

Also look at:

http://www.w8pgw.org/wp-content/uploads/ExtraClassE5A.pdf

I'm pretty sure the resistor has no effect on the resonant frequency, but it might affect the actual voltage across the capacitor. I think that at resonance the 10 Ohm resistor has a larger impedance by a factor of 5.