Electricity and Magnetism · Problem 8.3

MAXWELL'S EQUATIONS AND ELECTROMAGNETIC WAVES — Edward Purcell & David Morin

Physics — E&M · underdamped-motion

Problem

A second-order homogeneous linear differential equation can be written in the general form of x¨+2αx˙+ω02x=0,\ddot{x} + 2\alpha\dot{x} + \omega_0^2 x = 0, where α\alpha and ω0\omega_0 are constants. (For the series RLCRLC circuit in Section 8.1, Eq. (8.2) gives these constants as α=R/2L\alpha = R/2L and ω02=1/LC\omega_0^2 = 1/LC.) From Problem 8.2 we know that there are two independent exponential solutions to this equation. Find these two solutions, and then show that, in the underdamped case where α<ω0\alpha < \omega_0, the general solution can be written in the form of Eq. (8.10).

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