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2008-04-01, 21:27
unction [x,y]=exf13(x0,y0,n,r,N,a,b)%给出一个函数，并给出自变量和掺变量
x=x0;y=y0;%给初值
for k=1:n%给出循环次数
x(k+1)=x(k)+r*x(k)*(1-x(k)/N)-a*x(k)*y(k);%给出循环公式
y(k+1)=b*x(k)*y(k);
end
[x,y]=exf13(50,10,100,1.5,100,0.025,0.02);%gei x,y fuzhi
k=0:100;
plot(k,z(:,1),k,z(:,2)),grid %hua tu
x=x0;y=y0;%给初值
for k=1:n%给出循环次数
x(k+1)=x(k)+r*x(k)*(1-x(k)/N)-a*x(k)*y(k);%给出循环公式
y(k+1)=b*x(k)*y(k);
end
[x,y]=exf13(50,10,100,1.5,100,0.025,0.02);%gei x,y fuzhi
k=0:100;
plot(k,z(:,1),k,z(:,2)),grid %hua tu