MATLAB: Solve with known variables

Question

Probobly basic but I've been trying for hours with Googleing and trying different things. Any help would be appricated.

All I'm trying to do is substitute the known variables (a,b,c) into eqn2 in this case and I cannot get S to spit out 1000 as I think it should.

Code:

a = -500;

b = 433;

c = -866;

syms a b c

eqn2 = (-0.5*a-0.866*c) == 1000;

S = solve(eqn2,[a,c])

Answer 1

With the values you provided, ‘eqn2’ equates to 0, so there is nothing to solve for.

That aside, you are solving one equation for two unknowns, so you will likely not get the result you intend:

syms a b c
% a = -500;
b = 433;
% c = -866;
eqn2 = (-0.5*a-0.866*c) == 1000;
S = solve(eqn2,[a,c]);
a = S.a
c = S.c

producing:

a =
-2000
 
c =
0

.