How to Substitute an array into an equation and solve it ?
3 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
So if i had a = [1 2 3] b = [4 5 6] c = [7 8 9]
and the equation is ax^2+bx+c = 0
How would i substitude the array and solve for x ?
0 commentaires
Réponses (1)
Ameer Hamza
le 15 Nov 2020
Modifié(e) : Ameer Hamza
le 15 Nov 2020
For the given value of a, b, and c, the equation have no real solutions. Following shows how to use fsolve() when the equations have solutions
a = [1 2 3];
b = [4 5 6];
c = [-7 -8 -9];
F = @(x) a(:).*x.^2+b(:).*x+c(:);
sol = fsolve(F, rand(3,1))
If you don't have optimization toolbox, then you can use fzero()
a = [1 2 3];
b = [4 5 6];
c = [-7 -8 -9];
sol = zeros(size(a));
for i=1:numel(a)
F = @(x) a(i).*x.^2+b(i).*x+c(i);
sol(i) = fzero(F, rand());
end
2 commentaires
Ameer Hamza
le 15 Nov 2020
No, you are not using subs() correct. Following shows how it needs to be done
syms x a b c
C = a * (x.^2) + (b * x) + c == 0;
x1 = subs(C,{a,b,c},{1,3,5});
solution = double(solve(x1,x));
Ameer Hamza
le 16 Nov 2020
Modifié(e) : Ameer Hamza
le 16 Nov 2020
If a, b, and c are arrays
syms x a b c
av = [1 2 3];
bv = [4 5 6];
cv = [7 8 9];
C = a * (x.^2) + (b * x) + c == 0;
solution = cell(size(av));
for i = 1:numel(av)
x1 = subs(C,{a,b,c},{av(i),bv(i),cv(i)});
solution{i} = double(solve(x1,x));
end
solution is a cell array, where each cell contain solution for a combination of a, b, and c.
Voir également
Catégories
En savoir plus sur Linear Algebra dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!