In an oscillating series RLC circuit, show that U/U, the fraction of the energy lost per cycle

In an oscillating series RLC circuit, show that ΔU/U, the fraction of the energy lost per cycle of oscillation, is given to a close approximation by 2πR/w L The quantity w L/R is often called the Q of the circuit (for quality). A high-Q circuit has low resistance and a low fractional energy loss (= 2π/Q) per cycle