Solve function returns polynomial

3 visualizaciones (últimos 30 días)
tyler Wallis
tyler Wallis el 9 de Feb. de 2018
Comentada: Walter Roberson el 9 de Feb. de 2018
I am trying to use the solve function to solve 2 equations with 2 unknowns (a whole number and an angle). I have already solved this by hand but I would like to figure out what I am doing wrong here for future problems and my own sanity. Any help would be appreciated! The answers are FXT_1=144 and Theta_1=38.3
syms FXT theta
F1T=1280;
F2T=50;
F6=70;
v12=0.27;
v21=0.06;
E1=45000;
E2=11000;
G12=4500;
e1T=F1T/E1;
gam6=F6/G12;
sigma1=FXT*cosd(theta)^2;
sigma2=FXT*sind(theta)^2;
sigma6=FXT*sind(theta)^2*cosd(theta)^2;
eqn1=(1/E1)*(sigma1-v12*sigma2)==e1T;
eqn2=-sigma6/G12==gam6;
sol=solve([eqn1,eqn2],[FXT,theta])
FXT_1=sol.FXT
Theta_1=sol.theta
  2 comentarios
Walter Roberson
Walter Roberson el 9 de Feb. de 2018
Editada: Walter Roberson el 9 de Feb. de 2018
FXT = -5074.671595, theta = 83.20726294
FXT = -5074.671595, theta = -83.20726294
FXT = 1195.771595, theta = 13.37182242*I
FXT = 1195.771595, theta = -13.37182242*I
FXT = -5074.671595, theta = 96.79273706
FXT = -5074.671595, theta = -96.79273706
FXT = 1195.771595, theta = 180.0000000-13.37182242*I
FXT = 1195.771595, theta = 180.0000000+13.37182242*I
and additional solutions for each theta value, every integer multiple of 360*pi .
My testing shows there are certainly no solutions near 144, 38.3
Walter Roberson
Walter Roberson el 9 de Feb. de 2018
With that sind()^2*cosd()^2 you have to expect that there might be a solution in every quadrant.

Iniciar sesión para comentar.

Respuestas (0)

Etiquetas

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by