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楼主 |
发表于 2014-4-10 19:37
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附上程序
clc
clear all
n=0;
m=1;k=1;kn=0.0005;C=0.02;F=1;
for w=0.7:0.01:1.4
n=n+1;
a=9*kn^2/16;b=3*kn*(k-m*w^2)/2;c=(k-m*w^2)^2+C^2*w^2;d=-F^2;
X=b^2-3*a*c;
Y=b*c-9*a*d;
Z=c^2-3*b*d;
delt=Y^2-4*X*Z;
delt1(n)=Y^2-4*X*Z;
if X==0&&Y==0
A1(n)=-b/(3*a);
A2(n)=-c/(b);
A3(n)=-3*d/(c);
else if delt>0
W1=X*b+3*a*(-Y+abs(sqrt(Y^2-4*X*Z)))/2;
W2=X*b+3*a*(-Y-abs(sqrt(Y^2-4*X*Z)))/2;
%W1=X*b+3*a*(-Y+sqrt(Y^2-4*X*Z))/2;
% W2=X*b+3*a*(-Y-sqrt(Y^2-4*X*Z))/2;
A1(n)=(-b-(W1^(1/3)+W2^(1/3)))/(3*a);
A2(n)=(-b+1/2*(W1^(1/3)+W2^(1/3))+sqrt(3)/2*(W1^(1/3)-W2^(1/3))*i)/(3*a);
A3(n)=(-b+1/2*(W1^(1/3)+W2^(1/3))-sqrt(3)/2*(W1^(1/3)-W2^(1/3))*i)/(3*a);
else if delt==0
K=Y/X;
A1(n)=-b/a+K;
A2(n)=-K/2;
A3(n)=-K/2;
else if delt<0
T=(2*X*b-3*a*Y)/(2*sqrt(X^3));
sita=acos(T);
A1(n)=(-b-2*sqrt(X)*cos(sita/3))/(3*a);
A2(n)=(-b+sqrt(X)*(cos(sita/3)+sqrt(3)*sin(sita/3)))/(3*a);
A3(n)=(-b+sqrt(X)*(cos(sita/3)-sqrt(3)*sin(sita/3)))/(3*a);
end
end
end
end
end
A1=sqrt(A1);
A2=sqrt(A2);
A3=sqrt(A3);
A1S=abs(A1);
A2S=abs(A2);
A3S=abs(A3);
w=0.7:0.01:1.4;
figure;plot(w,A1S,'+',w,A2S,'.',w,A3S,'*');
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