无阻尼二自由系统固有频率的程序

shouce

% 无阻尼二自由系统固有频率的程序 20180401A
9 \2 m: g. @) k( m& ]( {* am1=100;m2=100;k1=200;k2=400;%
( h6 |9 I5 Q$ d5 _c1=0;c2=0;
: n% ^7 c* Q, P6 q$ l& h: {x0=[1;0];xd0=[0;0];tf=50;dt=0.1;
M=[m1,0;0,m2];k=[k1+k2,-k2;-k2,k2];
c=[c1+c2,-c2;-c2,c2];
A=[zeros(2,2),eye(2);-M\k,-M\c];
; M# N& \) c1 y0 S4 s( t! o3 ^' o. L( m; Gy0=[x0;xd0];
for i=1:round(tf/dt)+1
; _, [7 P& v# o9 c( A! s! t    t(i)=dt*(i-1)
. u( p/ |2 K" A0 S( d7 F) _- {    y(:,i)=expm(A*t(i))*y0;
5 ^8 ~7 O; m7 q! T1 eend
* m7 b- X; S3 b( j& B. Isubplot(2,1,1),plot(t,y(1,),grid  
subplot(2,1,2),plot(t,y(2,),grid
9 c1 j4 K! l' W! O6 G[p,lamda]=eig(A)




lamda =
# N) A( w$ y6 \, g- }: [" U  Columns 1 through 2
  0.000000000000000 + 3.020447918044219i  0.000000000000000 + 0.000000000000000i
  0.000000000000000 + 0.000000000000000i  0.000000000000000 - 3.020447918044219i
5 X% ?. L6 q& }4 x  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
/ M5 `$ S4 Q! G, \  t2 w& p# t  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
) b, ]1 I# Q, o" \/ ]# b  Columns 3 through 4
  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
% L- m- ]% G4 G8 D; M  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
-0.000000000000000 + 0.936426384924271i  0.000000000000000 + 0.000000000000000i
. |$ l9 X( H3 A  0.000000000000000 + 0.000000000000000i -0.000000000000000 - 0.936426384924271i
& I. Z9 p- f( E; h* \

0 J6 s0 k" c" Z) U* Z* p

鸿鹄重工

代码中有个笑脸是啥意思，此处应该是什么代码？