how to plot curve in matlab

Hi. How can i plot below equation?

thank you very much

f=(31*f^6)/49000000000 - (667*f^2)/39200 - (657*f^4)/98000000 - (375*cos(qa))/28 - (f^2*cos(qa))/400 + (3*f^4*cos(qa))/7000000 + 375/28;

[Star Strider]

Sincce ‘f’ appears on both sides of the equation, what do you want to do?

[saman ahmadi]

Excuse me, it is below, I want to plot curve(qa vs f). thank you

(31*f^6)/49000000000 - (667*f^2)/39200 - (657*f^4)/98000000 - (375*cos(qa))/28 - (f^2*cos(qa))/400 + (3*f^4*cos(qa))/7000000 + 375/28=0;

[David Hill]

For each qa there potentailly could be six real solutions for f. How do you want to plot that? You could plot the equation's value for different values of qa. For example:

qa=pi/4;%change qa to desired values.
y=@(f)(31*f.^6)/49000000000 - (667*f.^2)/39200 - (657*f.^4)/98000000 - (375*cos(qa))/28 - (f.^2*cos(qa))/400 + (3*f.^4*cos(qa))/7000000 + 375/28;
f=-115:.01:115;
plot(f,y(f));

Answer 1

[KSSV]

Are you looking for something like this?

qa = linspace(-pi,+pi,200) ; % give your ranges 
f= linspace(-115,115,200) ;  % give your ranges 
[f,qa] = meshgrid(f,qa) ;  % for a mesh 
y=@(f,qa)(31*f.^6)/49000000000 - (667*f.^2)/39200 - (657*f.^4)/98000000 - (375*cos(qa))/28 - (f.^2.*cos(qa))/400 + (3*f.^4.*cos(qa))/7000000 + 375/28;
y = y(f,qa) ; 
contour(f,qa,y,[0 0])