Question

d²x 4. Show that x (t) = xm exp(−ßt) exp(±iwt) is a solution of the equation m dt² kx = 0, where w and ß are defined by functions of m, k, and b. (10 pts) dx dt

Answer 1

We have given that the displacement of an object is given as x(t) = xm exp(−ßt) exp(±iωt)Here,xm = Maximum displacement at time t = 0ß = Damping coefficientω = Angular frequencyTo prove that x(t) is the solution to m d²x/dt² + kx = 0, where w and ß are defined by functions of m, k, and b, we need to differentiate the given equation and substitute it in the above differential equation.Differentiate x(t) with respect to t:dx(t)/dt = -xmß exp(-ßt) exp(±iωt) + xm(±iω) exp(-ßt) exp(±iωt) = xm[-ß + iω] exp(-ßt) exp(±iωt)Differentiate x(t) again with respect to t:d²x(t)/dt² = xm[(-ß + iω)²] exp(-ßt) exp(±iωt) = xm[ß² - ω² - 2iβω] exp(-ßt) exp(±iωt)Substituting these in the given differential equation:m d²x/dt² + kx = 0=> m [ß² - ω² - 2iβω] exp(-ßt) exp(±iωt) + k xm exp(-ßt) exp(±iωt) = 0=> exp(-ßt) exp(±iωt) [m(ß² - ω² - 2iβω) + kxm] = 0From this equation, we can conclude that x(t) satisfies the differential equation. Hence, the given equation is the solution to the differential equation.