题目

已知两个同频率、同方向的简谐振动[ x_1 = A cos (omega t + (3pi)/(4)) ][ x_2 = 3A cos (omega t - (pi)/(4)) ]（SI）。则合振动的振动方程应为【 】A. x = 2A cos (omega t - (pi)/(4)) B. x = 2A cos (omega t + (3pi)/(4)) C. x = 4A cos (omega t + (pi)/(2)) D. x = 4A cos (omega t - (pi)/(4))

已知两个同频率、同方向的简谐振动 $x_1 = A \cos (\omega t + \frac{3\pi}{4})$ $x_2 = 3A \cos (\omega t - \frac{\pi}{4})$ （SI）。则合振动的振动方程应为【 】

A. $ x = 2A \cos (\omega t - \frac{\pi}{4}) $

B. $ x = 2A \cos (\omega t + \frac{3\pi}{4}) $

C. $ x = 4A \cos (\omega t + \frac{\pi}{2}) $

D. $ x = 4A \cos (\omega t - \frac{\pi}{4}) $

题目解答

答案

A. $ x = 2A \cos (\omega t - \frac{\pi}{4}) $