1 % Demo: Graphics Method GM
2 % Test : 8 - 4.5*(x - sin(x)) = 0
3 clc
4 disp('Demo: Graphics Method')
5 disp('======================')
6 x = -1:0.1:4;
7 fun = 8 - 4.5*(x - sin(x));
8 data = [x' fun']
9 % plotear:
10 plot(x,fun,'LineWidth',2)
11 hold on
12 xlabel('Eje(x)','FontSize', 18)
13 ylabel('Fun(x)', 'FontSize', 18)
14 title('Demo: Graphics Method', 'FontSize', 16)
15 grid on
16 xsol = 2.43
17 plot(xsol, 0,'r*', 'LineWidth', 10)
18
19
1 %Demo : Solucion Ecuacion de Segundo Grado
2 % ax^2 + bx + c =0
3 % Input: a, b,c
4 % Output: x1, x2
5 clc
6 disp('Demo : Equation Solution Second Degree')
7 disp('=======================================')
8 a=input('valor de a = ');
9 b=input('valor de b = ');
10 c=input('valor de c = ');
11 % main:
12 d=b^2-4*a*c; % discriminate
13 if d>0
14 disp('')
15 disp('raices reales y diferentes')
16 x1=(-b+sqrt(d))/(2*a);
17 x2=(-b-sqrt(d))/(2*a);
18
19 elseif d==0
20 disp('')
21 disp('raices reales e iguales')
22 x1=-b/(2*a);
23 x2=-b/(2*a);
24
25 else
26 disp('')
27 disp('raices complejas y conjugadas')
28 x1=(-b+i*sqrt(-d))/(2*a);
29 x2=(-b-i*sqrt(-d))/(2*a);
30
31 end
32 disp('')
33 disp('valores de la ecuación de segundo grado:')
34 x1 , x2
1 %Demo: Bisection Method
2 % File : bisection.m
3 % Author: Numerical Methods
4 % teste : 8-4.5*(x - sin(x))=0
5 % Initial interal : a=2, b=3
6 % Code M-File
7 clc
8 disp('Demo : Bisection Method')
9 disp('=======================')
10 % Input
11 a=2,b=3 %[a,b] intervalo de busqueda inicial
12 imax = 20 % numero maximo de teraciones permitidas
13 tol = 10^(-3) % error maximo permitido
14 fun = @(x) 8-4.5*(x - sin(x))
15 % main
16 fa = fun(a);
17 fb = fun(b);
18 if fa*fb >0
19 disp('No hay solucion en el intervalo [a,b]')
20 else
21 disp('i a b xs f(xs) tol ')
22 disp('=================================================================')
23 for i = 1:imax
24 xs = (a+b)/2;
25 toli= (b-a)/2;
26 fxs = fun(xs);
27 fprintf('%3i %11.6f %11.6f %11.6f %11.6f %11.6f\n',i,a,b,xs,fxs,toli)
28 if fxs == 0
29 fprintf('solucion exacta x = %11.6f encontrada',xs)
30 break
31 endif
32
33 if toli < tol
34 break
35 endif
36
37 if i == imax
38 fprintf('Solucion no fue obtenida en % i iteraciones', imax)
39 break
40 endif
41
42 if fun(a)*fxs < 0
43 b = xs;
44 else
45 a = xs;
46 endif
47 end
48
49 endif
50 fprintf('\n\n')
51 fprintf('solucion xs = %11.6f\n', xs)
52
