無阻尼二自由系統(tǒng)固有頻率的程序

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% 無阻尼二自由系統(tǒng)固有頻率的程序 20180401A
m1=100;m2=100;k1=200;k2=400;%
c1=0;c2=0;
" k  v9 c, @9 Nx0=[1;0];xd0=[0;0];tf=50;dt=0.1;
M=[m1,0;0,m2];k=[k1+k2,-k2;-k2,k2];
- R% j- n/ i- f- P6 q) O' k( ac=[c1+c2,-c2;-c2,c2];
A=[zeros(2,2),eye(2);-M\k,-M\c];
7 A! @, K* ^" U& t% ^+ Z6 gy0=[x0;xd0];
" _  I! k! k# `, A+ }for i=1:round(tf/dt)+1
    t(i)=dt*(i-1)
    y(:,i)=expm(A*t(i))*y0;
end
subplot(2,1,1),plot(t,y(1,),grid  
subplot(2,1,2),plot(t,y(2,),grid
8 m% U# k. U5 k[p,lamda]=eig(A)

2 Z$ a* S$ d- `  a3 v% K

% g+ p- l8 ]- O4 s3 V* G
lamda =
  Columns 1 through 2
  0.000000000000000 + 3.020447918044219i  0.000000000000000 + 0.000000000000000i
3 A. @4 a7 G* N. o* o  0.000000000000000 + 0.000000000000000i  0.000000000000000 - 3.020447918044219i
  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
" `4 q/ I. W9 Q  Columns 3 through 4
  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
9 v# C* \: e% N3 d/ P2 i. C4 D% E4 @  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
2 r; E" t2 ~$ y( u( n/ | -0.000000000000000 + 0.936426384924271i  0.000000000000000 + 0.000000000000000i
8 M  N& T9 K. `- b  |& t- q  0.000000000000000 + 0.000000000000000i -0.000000000000000 - 0.936426384924271i
4 Y4 U9 G( x1 S" I- ?" s6 F

5 W+ J% X1 X7 |. n1 r; B

鴻鵠重工

代碼中有個(gè)笑臉是啥意思,，此處應(yīng)該是什么代碼,？