解方程的二分法 matlab 程序

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解方程的二分法  matlab 程序  （ x^3-3*x^2+6*x-1=0）

% Bisection.m
) ~. B$ e5 @/ s" g. g3 F; ?7 k+ bfunction[k,x,f_value]=Bisection(f,a,b,eps1,eps2,N)
fprintf('k ,a ,b ,x, f\n')
% |. @  D" F/ v9 mfor k=1:N
( ~' y$ s" m5 J    x=(a+b)/2;
    f_value=f(x);
    fprintf( '%3d, %10.9f, %10.9f, %10.9f,%10.9f,\n'...
2 a7 i0 E! C8 u$ T" q: d1 l+ B+ ]      ,k ,a ,b ,x, f_value)
$ R8 n  m, }( S* x; R* m/ M2 ?" h    if abs(f_value)< eps1||0.5*(b-a)<eps2
    return
' |! \( ^# Y6 L* f    else
4 P- W9 g5 K: Q; o5 b, c        if f(x)*f(a)<0
          b=x;
        else
) ]# u1 m6 Y7 f! Y4 Z          a=x;
        end
        if k== N
" r- R  y$ b* [/ c) t. S8 l7 O- N          warning ('算法超出最大迭代數!')   
! e- U' r+ {9 ^0 r( P& ]        end
    end
. b( L* s) Z% Y; W* W: S! b4 h+ u) m
% examlpe7.m
a=0; b=1;
5 m, o- ]4 E. P' w9 Y) ?; s* aeps1=1e-4;eps2=1e-4;
& S3 }  m5 T! S  N* D0 i5 F: V4 M9 R N=300;
: f) b6 N6 @( s  l: Hf=@ (x) (x^3-3*x^2+6*x-1);
- B  b0 O- p! O) g! `Hfun=@Bisection;
[k,x,f_value]= feval(Hfun, f,a,b,eps1,eps2,N);

運行結果
>> examlpe7
k ,a ,b ,x, f
  1, 0.000000000, 1.000000000, 0.500000000,1.375000000,
  2, 0.000000000, 0.500000000, 0.250000000,0.328125000,
  3, 0.000000000, 0.250000000, 0.125000000,-0.294921875,
  4, 0.125000000, 0.250000000, 0.187500000,0.026123047,
! t5 b' @$ _9 L$ Y3 S5 z& j+ h% i  5, 0.125000000, 0.187500000, 0.156250000,-0.131927490,
$ z+ m, }) R6 V! S( x/ s  6, 0.156250000, 0.187500000, 0.171875000,-0.052295685,
  7, 0.171875000, 0.187500000, 0.179687500,-0.012936115,
$ q( F5 I2 ~- x/ q  8, 0.179687500, 0.187500000, 0.183593750,0.006630838,
  9, 0.179687500, 0.183593750, 0.181640625,-0.003143273,
' V' S0 h5 Q& ?) g  g- ` 10, 0.181640625, 0.183593750, 0.182617188,0.001746121,
11, 0.181640625, 0.182617188, 0.182128906,-0.000697991,
12, 0.182128906, 0.182617188, 0.182373047,0.000524211,
# J0 y  E4 ]5 q 13, 0.182128906, 0.182373047, 0.182250977,-0.000086854,