在某个音乐厅内，原始音频信号的回音由于墙壁和天花板等的反射而产生，听众所感受到的音频信号是 和它的回音的合成。令y(n)=x(n)+ax(n-k),其中x(n)=cos(0.3pin)+0.5cis(0.6pin),a=0.1,k=50.产生100个样本，使用Matlab工具，求出其自相关，从中观测确定a和k.

-In a concert hall, the original audio signal echo the walls and ceilings due to the reflection of such production, the audience felt the audio signal is and its echo synthesis. So that y (n) = x (n)+ ax (nk), where x (n) = cos (0.3pin)+0.5 cis (0.6pin), a = 0.1, k = 50. Generate 100 samples, using Matlab tools, find the self-related, from observation to determine a and k.