i want to plot this physics problem ... but after run programme ..give me error in plot,, but i cant determine where the exact error

syms x; syms E; syms A; syms B; syms K; syms T; syms v;

n=1*10^19; %number of electrons area=1*10^-3; %area A=2; w=1*10^-4; %width q=1.6*10^-19; h=6.6*10^-34; v=1*10^6; % electron velocity K=1.38*10^-23; %boltzman constant m=0.5; %effective mass

 Va=0.1:0.1:5        %applied voltage
 E=Va/w;
x=(q*Va)/w;

B=A*x.^2; a=sqrt((E-A)./B); %Twkb=(1./(sqrt(2.*m.*B.*((a.^2)+1./(x.^2)))))*exp((2*sqrt(2.*m*B/(h.^2)))*((-sqrt(a.^2+(1./x.^2))./(1./x))+log((1./x)+sqrt(a.^2+(1./x.^2))))); Twkb=(1./(sqrt(2*m./x.^2))).*exp((2*sqrt(m.*B/2*h.^2)).*((-sqrt(a.^2+(1./x.^2))./(1./x))+log((1./x)+sqrt(a.^2+(1./x.^2)))));

 I=area.*q.*v.*n.*Twkb

fplot(Va ,I ,'*','r') xlabel('Applied Voltage (Va)in Volts') ylabel('current in(A)')

%I=((q.^2)/(pi*h))*Tw(E,A,B,x)*K*T*log(0.5*(1+cosh(v/(K*T))))

Answer 1

[madhan ravi]

syms x E A B K T v

n=1*10^19; 

area=1*10^-3; 

A=2; 
w=1*10^-4; 
q=1.6*10^-19; 
h=6.6*10^-34; 
v=1*10^6; 
K=1.38*10^-23; 
 m=0.5; 

Va=0.1:0.1:5   %applied voltage

E=Va/w;

x=(q*Va)/w;

B=A*x.^2; a=sqrt((E-A)./B); 

Twkb=(1./(sqrt(2.*m.*B.*((a.^2)+1./(x.^2))))).*exp((2.*sqrt(2.*m*B/(h.^2))).*((-sqrt(a.^2+(1./x.^2))./(1./x))+log((1./x)+sqrt(a.^2+(1./x.^2)))));

Twkb=(1./(sqrt(2.*m./x.^2))).*exp((2.*sqrt(m.*B/2.*h.^2)).*((-sqrt(a.^2+(1./x.^2))./(1./x))+log((1./x)+sqrt(a.^2+(1./x.^2)))));

   I=area.*q.*v.*n.*Twkb

   I=((q.^2)/(pi.*h)).*Tw(E,A,B,x).*K.*T*log(0.5.*(1+cosh(v/(K.*T))))

fplot(Va ,I) 

xlabel('Applied Voltage (Va)in Volts') 

ylabel('current in(A)')

[madhan ravi]

Undefined function or variable 'Tw'.

Error in COMMUNITY (line 30)
 I=((q.^2)/(pi.*h)).*Tw(E,A,B,x).*K.*T*log(0.5.*(1+cosh(v/(K.*T))))

[madhan ravi]

fplot command can be used only for function which is dependent on one variable.

[Aalaa Abu alrob]

i use a plot command ,, but i cant define a special color !!

[madhan ravi]

plot(Va,I,'r')

[madhan ravi]

Read the link below to define markers for your plot:

https://www.mathworks.com/help/matlab/ref/linespec.html