How do you graph two equations on the same graph?

Here is the code that I am using for my two equations I am able to graph them separately but when I graph them together my graph is not correct. I am trying to figure out where the two equations intersect.

plot 1

x = 0:.1:10;

I = (-1/5000)*x+(.0018);

plot(x,I)

plot 2

q=1.6022e-19

C=28.73

T=273+C

k=1.3806e-23

Is=1.0e-12

V= 0:0.01:9

n=1

Vt=(k*T)/q

Id=Is*((exp(V/(n*Vt)))-1)

plot(V,Id)

Answer 1

[Star Strider]

Considering your present code, use the hold function.

Using your code:

x = 0:.1:10;
I = (-1/5000)*x+(.0018);
plot(x,I)
hold on                                         % hold on
q=1.6022e-19    
C=28.73            
T=273+C         
k=1.3806e-23   
Is=1.0e-12      
V= 0:0.01:9  
n=1 
Vt=(k*T)/q  
Id=Is*((exp(V/(n*Vt)))-1)   
plot(V,Id)
hold off                                        % hold off

Experiment to get the result you want.

Answer 2

[Sulaymon Eshkabilov]

Hi,

x = 0:.1:10;
I = (-1/5000)*x+(.0018);
plot(x,I), hold on
%plot 2
q=1.6022e-19;    
C=28.73 ;           
T=273+C;         
k=1.3806e-23 ;  
Is=1.0e-12  ;    
V= 0:0.01:9;  
n=1 ;
Vt=(k*T)/q  ;
Id=Is*((exp(V/(n*Vt)))-1) ;  
plot(V,Id), legend('x vs. I', 'V vs. Id')

% as two subplots
figure
subplot(211)
plot(x, I)
subplot(212)
plot(V, Id)

Check the values of coefficients/parameters. They seem to be incorrectly typed in.