Solving a symbolic array

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mattyice 2016-5-19

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https://ww2.mathworks.cn/matlabcentral/answers/284898-solving-a-symbolic-array

编辑： mattyice 2016-5-19

Im trying to solve an equation that has an array of different values. In the following code, I want to solve for x at different values of T where T=[50:1:1000]. The code works when T is a single element, but not when it is a matrix. I get this error:

Error using mupadengine/feval (line 163) The number of equations exceeds the number of indeterminates. This is allowed only for polynomial systems.

Error in sym/vpasolve (line 172) sol = eng.feval('symobj::vpasolve',eqns,vars,X0);

Error in HW5 (line 27) Efv=vpasolve(LHS==(ni.^2),x);

--------------------------------------------------------------------------------------------------------------- Here is the code:

close all
clear all
syms x
Econv=1.60218*10^-19; %%J/eV
Eg=1.11;             %%Bandgap energy in eV
k=(1.38064852*10^-23)/Econv;   %%Bolzmann Constant in eV/K
m0=9.109*10^-31;     %%Mass of electron
mn=1.1*m0;           %%Mass of e carrier
mp=0.58*m0;           %%Mass of e hole
Eion=0.045;
hbar=1.054571800*10^-34;   %Planck's constant in Js
Nd=((10^15)*(100)^3);      %%#Donors/m^3
T=[50:1:1000];
Nc=2.*(mn*Econv*k.*T./(2*pi*hbar^2)).^(3/2);
Nv=2.*(mp*Econv*k.*T./(2*pi*hbar^2)).^(3/2);
Eiv=Eg/2+(3/4)*k.*T.*log(mp/mn);
ni=((Nc.*Nv).^(1/2)).*exp(-Eg./(2*k.*T));
p=ni.*exp(-x./(k.*T)).*(exp(Eiv./(k.*T)));
Ndion=Nd./(1+exp(x./(k.*T)).*exp((Eion-Eg)./(k.*T)));
LHS=p.*(p+Ndion);
Efv=vpasolve(LHS==(ni.^2),x);