Solve Equation and Plot it
20 visualizaciones (últimos 30 días)
Mostrar comentarios más antiguos
Daniela Würmseer
el 17 de Jun. de 2022
Comentada: Star Strider
el 17 de Jun. de 2022
Hello, i have the follwing equation:
0 = 0.5*alpha*(w(1)*f_1-w(2)*f_2)^2+p(1)*f_1+p(2)*f_2+skalar- AF_z
which i want to write like f_2 = ... and plot after f_2 for f_1 = linspaces(0,20).
At this moment we already know that alpha = 0.4207, skalar = 4.5375, AF_z = 5,9796, w = [0.77,0.23], p = [-0.9851,0.5243]. So the only values we do not know is f_1 and f_2
So i started like this:
syms f_1 f_2
g = 0.5*alpha*(w(1)*f_1-w(2)*f_2)^2+p(1)*f_1+p(2)*f_2+skalar- AF_z;
x = solve(g,f_2);
As there is a root (+/- sqrt), when reshaping the equation to f2 =..., the structure of x is 2x1 sym.
And now i want to plot for all f_1 betweem 0 and 20 the f_2 values.
I know that i need to use fplot.
The solution should look like the pic.
Thank you already for the help
0 comentarios
Respuesta aceptada
Star Strider
el 17 de Jun. de 2022
The result ie not exactly the same as the plot in the original question, however it is close —
alpha = 0.4207;
skalar = 4.5375;
AF_z = 5.9796;
w = [0.77,0.23];
p = [-0.9851,0.5243];
syms f_1 f_2
g = 0.5*alpha*(w(1)*f_1-w(2)*f_2)^2+p(1)*f_1+p(2)*f_2+skalar- AF_z;
x = solve(g,f_2)
figure
fplot(x, [0 10])
grid
xlim([0 20])
The dashed vertical line denotes a singularity at .
.
2 comentarios
Más respuestas (1)
John D'Errico
el 17 de Jun. de 2022
Editada: John D'Errico
el 17 de Jun. de 2022
Easy peasy. Essentially one line of code once you define the various constants.
syms f_1 f_2
alpha = 0.4207;
skalar = 4.5375;
AF_z = 5.9796; % You wrote 5,9796 but note that numbers in matlab are written with decimal points, not commas.
w = [0.77,0.23];
p = [-0.9851,0.5243];
fimplicit(0 == 0.5*alpha*(w(1)*f_1-w(2)*f_2)^2+p(1)*f_1+p(2)*f_2+skalar- AF_z,[-5 10 -10 20])
The exact shape will of course depend on the exact constants used. It appears the constants were subtly different to create the figure you posted.
Ver también
Categorías
Más información sobre Calculus en Help Center y File Exchange.
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!