MATLAB: What’s wrong with this code , the graphs appears empty

for loopgraph

clc
clear
T1=100;  %C°

T_inf=20; %C°
A=1 ; %m

%K=1 , L=.01 m , h=10  
  %Ts=(k*T1+h*L*T_inf)\(k+h*L)
  %Q=K*A*(T1-Ts)\L ;
for  h = 1:100 
Ts=((1*100)+(20.*h.*.01)).\((.01.*h)+1)    %from Qcond=Qconv 

Q=1*1*(100-Ts)\0.01  
 subplot(2,2,1) , plot(h,Q,'r'), hold on ;
axis([1,100,50,4000])
 title(' Fig.1')
 xlabel('convective heat transfer coefficient (h)','fontsize',[10]) ;
ylabel('Heat Transfer per unit Area (Q)') ; grid on
end
   for k=0.1:50 
Ts=((k.*100)+(10*.01*20)).\((10*.01)+k) ; 
Q=k.*1*(100-Ts).\0.01  
subplot(2,2,2) , plot(k,Q,'b') , hold on ;
 title(' Fig.2')
 xlabel('  Thermal conductivity (k)','fontsize',[10]) ;
ylabel('Heat Transfer per unit Area (Q)') ; grid on
   end
 for  l=.01:.1  %m
Ts=((1*100)+(l.*10.*20)).\((10*l)+1) ; %from Qcond=Qconv 
Q=1*1*(100-Ts).\l  
  subplot(2,2,3) , plot(l,Q,'g') , hold on ;
 title(' Fig.3')
 xlabel('wall Thickness (L)','fontsize',[10]) ;
ylabel('Heat Transfer per unit Area (Q)') ; grid on
 end

Best Answer

You are plotting one point at a time. The default marker is 'none'. You need to specify a marker if you want points to be visible when you plot them one at a time.
If you want your points to be connected by a line then you need to save the values and then plot() after they are all known.
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