Matlab ~ linear equation?

Question

do any one know how to solve this equation in MATLAB?

F_I*cosd(alpha_I) - F_C(cosd(alpha_C)) = 0  
F_I*sind(alpha_I) - F_T_1 + F_C*sind(alpha_C) = 0  
F_T_1*abs(x_F_C-x_T_1) - F_I*sind(alpha_I)*abs(x_F_C-x_F_I) - F_I*cosd(alpha_I)*abs(y_F_C-y_F_I) = 0  

I KNOW:

alpha_I | F_T_1 | x_F_C | x_T_1 | x_F_I | y_F_C | y_F_I

I DON'T know (and want to know):

F_I | F_C | alpha_C

The problem is in F_C*cosd(alpha_C), which are two variables so I don't know what to write in Ax=B matrix in A.

Answer 1

The third equation contains only one unknown, namely F_I . You can therefore explicitly solve for that, which leaves you with only two equations and two unknowns:

F_I= (F_T_1*abs(x_F_C-x_T_1)/(sind(alpha_I)*abs(x_F_C-x_F_I)+cosd(alpha_I)*abs(y_F_C-y_F_I))

Now your first two equations are basically of the form

a*sind(b)=c
a*cosd(b)=d

With a, b unknown. Divide them to get

tand(b) = c/d

This gives you b (alpha_C), and now solving for a (F_C) is trivial.