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376981713金蟲(chóng) (小有名氣)
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[求助]
求解二元二次方程組
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x-y=A(1-x)^2 y^2=2B(x-y)(1-y)基中A,B是已知的,且A,B相對(duì)應(yīng)有100組數(shù),所以我想在excel中計(jì)算,算一組就自動(dòng)得出其他!求高人指點(diǎn)!如果不能用excel應(yīng)該怎么處理! |
專家顧問(wèn) (職業(yè)作家)
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專家經(jīng)驗(yàn): +831 |
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由第一式得:y=x-A*(1-x)^2 代入第二式得:1+2*(x-1)+(-2*A+1)*(x-1)^2+(-2*A+2*B*A)*(x-1)^3+(A^2-2*B*A^2)*(x-1)^4=0 上式是關(guān)于(x-1)的四次方程!可由四次方程求根公式求解! |

專家顧問(wèn) (職業(yè)作家)
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專家經(jīng)驗(yàn): +831 |

專家顧問(wèn) (職業(yè)作家)
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專家經(jīng)驗(yàn): +831 |
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程序里面的AB.txt文件是你的數(shù)據(jù)! function fcqiujie AB=textread('AB.txt'); N=size(AB,1); A=AB(:,1);B=AB(:,2); tx=zeros(N,4); for i=1:N tx(i, =roots([(A(i)^2-2*B(i)*A(i)^2),(-2*A(i)+2*B(i)*A(i)),(-2*A(i)+1),2,1])';end x=tx+1; for i=1:N y(i, =x(i, -A(i)*(1-x(i, ).^2;end for i=1:N idx=find(imag(x(i, )==0&real(x(i, )<1);idy=find(imag(y(i, )==0&real(y(i, )<1);id=intersect(idx,idy); if length(id)==1 disp(['x(',num2str(i),')=',num2str(x(i,id),7),' ','y(',num2str(i),')=',num2str(y(i,id),7),]); else disp(['x(',num2str(i),')=',num2str(x(i,id),7),' ','y(',num2str(i),')=',num2str(y(i,id),7),]); end end |

專家顧問(wèn) (職業(yè)作家)
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專家經(jīng)驗(yàn): +831 |
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function fcqiujie AB=textread('AB.txt'); N=size(AB,1); A=AB(:,1);B=AB(:,2); tx=zeros(N,4); for i=1:N tx(i, =roots([(A(i)^2-2*B(i)*A(i)^2),(-2*A(i)+2*B(i)*A(i)),(-2*A(i)+1),2,1])';end x=tx+1; for i=1:N y(i, =x(i, -A(i)*(1-x(i, ).^2;end for i=1:N idx=find(imag(x(i, )==0&real(x(i, )<1);idy=find(imag(y(i, )==0&real(y(i, )<1);id=intersect(idx,idy); if length(id)==1 disp(['x(',num2str(i),')=',num2str(x(i,id),7),' ','y(',num2str(i),')=',num2str(y(i,id),7),]); else disp(['x(',num2str(i),')=',num2str(x(i,id),7),' ','y(',num2str(i),')=',num2str(y(i,id),7),]); end end |

專家顧問(wèn) (職業(yè)作家)
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專家經(jīng)驗(yàn): +831 |
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x(1)=0.9997559 0.9998253 y(1)=-0.8649408 0.04513399 x(2)=0.9997509 0.9998288 y(2)=-0.941755 0.08290534 x(3)=0.9997463 0.9998319 y(3)=-1.013453 0.1155603 x(4)=0.9997421 0.9998346 y(4)=-1.081342 0.1444069 x(5)=0.9997381 0.9998372 y(5)=-1.146264 0.1702852 x(6)=0.9997343 0.9998395 y(6)=-1.208794 0.193772 x(7)=0.9997307 0.9998416 y(7)=-1.269348 0.215283 x(8)=0.9997272 0.9998436 y(8)=-1.328237 0.2351294 x(9)=0.9997239 0.9998455 y(9)=-1.385702 0.2535512 x(10)=0.9997206 0.9998473 y(10)=-1.441932 0.2707376 x(11)=0.9997175 0.999849 y(11)=-1.497078 0.2868413 x(12)=0.9997144 0.9998506 y(12)=-1.551267 0.3019872 x(13)=0.9997115 0.9998522 y(13)=-1.604602 0.3162789 x(14)=0.9997086 0.9998536 y(14)=-1.65717 0.3298037 x(15)=0.9997057 0.9998551 y(15)=-1.709046 0.3426356 x(16)=0.999703 0.9998564 y(16)=-1.760292 0.3548384 x(17)=0.9997003 0.9998577 y(17)=-1.810963 0.3664669 x(18)=0.9996976 0.999859 y(18)=-1.861109 0.3775692 x(19)=0.999695 0.9998602 y(19)=-1.91077 0.3881872 x(20)=0.9996924 0.9998613 y(20)=-1.959985 0.3983582 x(21)=0.9996802 0.9998666 y(21)=-2.20039 0.4435457 x(22)=0.9996687 0.9998712 y(22)=-2.43336 0.4812982 x(23)=0.9996579 0.9998753 y(23)=-2.660799 0.5135192 x(24)=0.9996477 0.9998789 y(24)=-2.883966 0.5414669 x(25)=0.9996378 0.9998822 y(25)=-3.103737 0.5660189 x(26)=0.9996284 0.9998852 y(26)=-3.320749 0.5878119 x(27)=0.9996192 0.999888 y(27)=-3.535481 0.6073231 x(28)=0.9996104 0.9998905 y(28)=-3.748297 0.6249193 x(29)=0.9996018 0.9998929 y(29)=-3.959487 0.6408881 x(30)=0.9995935 0.9998951 y(30)=-4.169279 0.6554595 x(31)=0.9995854 0.9998971 y(31)=-4.377861 0.6688198 x(32)=0.9995775 0.9998991 y(32)=-4.585385 0.681122 x(33)=0.9995697 0.9999009 y(33)=-4.791979 0.6924936 x(34)=0.9995621 0.9999026 y(34)=-4.997748 0.7030411 x(35)=0.9995547 0.9999042 y(35)=-5.202785 0.712855 x(36)=0.9995474 0.9999057 y(36)=-5.407165 0.7220124 |

金蟲(chóng) (小有名氣)
金蟲(chóng) (小有名氣)
金蟲(chóng) (小有名氣)
榮譽(yù)版主 (文壇精英)
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專家經(jīng)驗(yàn): +518 |
榮譽(yù)版主 (文壇精英)
![]() |
專家經(jīng)驗(yàn): +518 |
金蟲(chóng) (小有名氣)
榮譽(yù)版主 (文壇精英)
![]() |
專家經(jīng)驗(yàn): +518 |
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fid = fopen('路徑及文件名','r'); [AB,COUNT] = fscanf(fid,'%5f',[2,50]); %% eg. 2列50行 參數(shù)A A=AB(1, ;參數(shù)B xB=AB(2, ;for k=1:50 %% 1+2*(x-1)+(-2*A+1)*(x-1)^2+(-2*A+2*B*A)*(x-1)^3+(A^2-2*B*A^2)*(x-1)^4=0 C4=A^2-2*B*A^2; C3=-2*A+2*B*A; C2=-2*A+1; C1=2; C0=1; C=[C4,C3,C2,C1,C0]; Root=(roots(C)); %% 打印或顯示: x=1+Root(4); x=1+Root(3); x=1+Root(2); x=1+Root(1); end; |
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