Chapter 1 Signals and systems 2. Periodic Complex Exponential and Sinusoidal signals ④ Period 2丌 ② Euler's relation(欧拉关系) ot e sin ot Jot coS at t sin at 2006 Fall2006 Fall Chapter 1 Signals and Systems 2. Periodic Complex Exponential and Sinusoidal Signals ① Period ② Euler’ s relation( 欧拉关系) 2 cos j t j t e e t    − + = j e e t j t j t 2 sin    − − = e t j t j t    = cos + sin 0 0 2   T =