# Matlab Displaying the Fit Equation On graph.

1. Apr 2, 2017

### Arman777

I have a lineer data and I want to write the equation of it on the graph.
The x axis is inverse distance (1/m) and I showed as "d"
The y axis is capacitance (C) and I showed it like "C"
My data name is d_C

Here my codes that I used for now
>> d=d_C(:,1);
>> C=d_C(:,2);
>> plot(d,C,'go');
>> hold on
>> xlabel('Inverse Distance (1/m)','Fontsize',21)
>> ylabel('Capacitance (C)','Fontsize',21)
>> title('Inverse Distance vs Capacitance,Part (A)','Fontsize',23)
>> grid on
>> p = polyfit(d,C,1)

p =

0.0003 0.0414

>> Cfit=polyval(p,d);
>> plot(d,Cfit,'-b');
>> h = legend('Data','Best fit','Location','southeast');
>> set(h,'Fontsize',20);

I just need to write the equation on the graph like probably y=0.0003x+0.0414 (I am not sure about this though).I need codes.I cant do it on manually

Any help would be great
Thanks

#### Attached Files:

• ###### Graph Pic.png
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Last edited: Apr 2, 2017
2. Apr 2, 2017

### lewando

From a MATLAB newsgroup post:

[p]=polyfit(...);
a = p(1)
b = p(2)
polyfit_str = ['y = ' num2str(a) ' *x + ' num2str(b)]
% polyfit_str will be : y = 4*x + 2
text(10,10,polyfit_str);

3. Apr 2, 2017

### Arman777

Thanks a lot.I did it