Problem set find the numerical solution of the following partial differential equation: 1.C - N Scheme %二阶波动方程的CN格式 A=[0,-1;-1,0;]; I=[1,0;0,1]; N=100;%空间划分多少步 h=1.0/100; t=0.0001; r=t/h; step=200;%时间步数 U=zeros(2,N+1); d=zeros(2,N+1); a11=1:N+1;a12=1:N+1;a21=1:N+1;a22=1:N+1; b11=1:N+1;b12=1...