Re: [問題] solve求解的問題
※ 引述《MuseLand (I will survive)》之銘言：
: %以下是有的數值
: packet1=300;
: packet2=300;
: packet3=300;
: Rsr1=30;
: Rsr2=30;
: Rr1d1=10;
: Rr1d2=10;
: Rr1d3=10;
: Rr2d1=10;
: Rr2d2=10;
: Rr2d3=10;
: Rsd1=30;
: Rsd2=30;
: Rsd3=30;
: %想利用下列等式求解Xr1d1 Xr1d2 Xr1d3 Xr2d1 Xr2d2 Xr2d3
: eq1 = 'Rsr1=Xr1d1+Xr1d2+Xr1d3';
: eq2 = 'Rsr2=Xr2d1+Xr2d2+Xr2d3';
: eq3 = 'Vr1d1=Xr1d1*Rr1d1/(Xr1d1+Rr1d1)';
: eq4 = 'Vr2d1=Xr2d1*Rr2d1/(Xr2d1+Rr2d1)';
: eq5 = 'Vr1d2=Xr1d2*Rr1d2/(Xr1d2+Rr1d2)';
: eq6 = 'Vr2d2=Xr2d2*Rr2d2/(Xr2d2+Rr2d2)';
: eq7 = 'Vr1d3=Xr1d3*Rr1d3/(Xr1d3+Rr1d3)';
: eq8 = 'Vr2d3=Xr2d3*Rr2d3/(Xr2d3+Rr2d3)';
: eq9 = 'packet1/(Rsd1+Vr1d1+Vr2d1)=packet2/(Rsd2+Vr1d2+Vr2d2)';
: eq10 = 'packet2/(Rsd2+Vr1d2+Vr2d2)=packet3/(Rsd3+Vr1d3+Vr2d3)';
: eq11 = 'packet1/(Rsd1+Vr1d1+Vr2d1)=packet3/(Rsd3+Vr1d3+Vr2d3)';
: [Xr1d1 Xr1d2 Xr1d3 Xr2d1 Xr2d2 Xr2d3 ] = solve(
: eq1,eq2,eq3,eq4,eq5,eq6,eq7,eq8,eq9,eq10,eq11 )
: 程式碼如上面
: 抱歉剛接觸matlab
: 原本想測試看看所以故意湊好解的數字
: 想說至少會有[10 10 10 10 10 10]這個解
: 可是卻只出現[ empty sym ]以及[]
: 請問是什麼原因
: 請板上的先進幫忙解惑一下 thanks
我直接用eq1~eq11 matlab解不出來
不過把eq3~eq8代到eq9~eq11就可以解
packet1=300;
packet2=300;
packet3=300;
Rsr1=30;
Rsr2=30;
Rr1d1=10;
Rr1d2=10;
Rr1d3=10;
Rr2d1=10;
Rr2d2=10;
Rr2d3=10;
Rsd1=30;
Rsd2=30;
Rsd3=30;
syms Xr1d1 Xr1d2 Xr1d3 Xr2d1 Xr2d2 Xr2d3 Vr1d1 Vr1d2 Vr1d3 Vr2d1 Vr2d2 Vr2d3
eq1 = -Rsr1+Xr1d1+Xr1d2+Xr1d3;
eq2 = -Rsr2+Xr2d1+Xr2d2+Xr2d3;
eq9 = -packet1/(Rsd1+Xr1d1*Rr1d1/(Xr1d1+Rr1d1)+Xr2d1*Rr2d1/(Xr2d1+Rr2d1))+...
packet2/(Rsd2+Xr1d2*Rr1d2/(Xr1d2+Rr1d2)+Xr2d2*Rr2d2/(Xr2d2+Rr2d2));
eq10 = -packet2/(Rsd2+Xr1d2*Rr1d2/(Xr1d2+Rr1d2)+Xr2d2*Rr2d2/(Xr2d2+Rr2d2))+...
packet3/(Rsd3+Xr1d3*Rr1d3/(Xr1d3+Rr1d3)+Xr2d3*Rr2d3/(Xr2d3+Rr2d3));
eq11 = -packet1/(Rsd1+Xr1d1*Rr1d1/(Xr1d1+Rr1d1)+Xr2d1*Rr2d1/(Xr2d1+Rr2d1))+...
packet3/(Rsd3+Xr1d3*Rr1d3/(Xr1d3+Rr1d3)+Xr2d3*Rr2d3/(Xr2d3+Rr2d3));
[Xr1d1 Xr1d2 Xr1d3 Xr2d1 Xr2d2 Xr2d3 ] = solve...
(eq1,eq2,eq9,eq10,eq11,'Xr1d1','Xr1d2','Xr1d3' ,'Xr2d1','Xr2d2','Xr2d3')
因為只有5條方程式解6個未知數 它會顯示警告
然後出來的解都是參數解 不知道是不是你要的
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