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）
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5 a: |- V/ s, ^% q- V2 C% Bisection.m
( l* {- L! c+ I) Y! F( {function[k,x,f_value]=Bisection(f,a,b,eps1,eps2,N)
- F" c  M& @6 Rfprintf('k ,a ,b ,x, f\n')
2 _/ S( U1 S6 J4 d+ u+ W9 @8 v0 ?for k=1:N
# X% ?0 G! f& |. Q+ k    x=(a+b)/2;
    f_value=f(x);
1 v! f* h( F2 _! U9 G    fprintf( '%3d, %10.9f, %10.9f, %10.9f,%10.9f,\n'...
      ,k ,a ,b ,x, f_value)
    if abs(f_value)< eps1||0.5*(b-a)<eps2
5 Z5 A: }( ?9 W    return
; Z+ `8 R# Q/ r' u$ {7 F7 I2 `    else
. j. K+ [2 {2 J. c' u        if f(x)*f(a)<0
: f. w# X1 o* ~          b=x;
        else
, z+ H4 d" t1 O5 ]- @          a=x;
        end
1 n. e- ~% A: c6 K8 m9 U        if k== N
          warning ('算法超出最大迭代數(shù)!')   
# Y/ y; M3 z' S3 \        end
    end

9 f4 r1 W& Z% I! }6 f' J% examlpe7.m
, E; h1 C; d; oa=0; b=1;
+ }4 t1 b, V3 }( [- ^; {2 a& `5 e8 W; weps1=1e-4;eps2=1e-4;
) W; C9 W/ n4 j3 J  | N=300;
# _1 X3 ^4 V& |9 r; I( d) Ef=@ (x) (x^3-3*x^2+6*x-1);
Hfun=@Bisection;
[k,x,f_value]= feval(Hfun, f,a,b,eps1,eps2,N);
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5 R8 K1 X; i  M& }運(yùn)行結(jié)果
& Z1 Z2 K2 B) j  Y" Q2 ^/ l>> 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,
' s- e9 C9 C0 W; B  4, 0.125000000, 0.250000000, 0.187500000,0.026123047,
6 S6 `& [$ ^+ M, Y* v* i! E4 D% m" e  5, 0.125000000, 0.187500000, 0.156250000,-0.131927490,
  6, 0.156250000, 0.187500000, 0.171875000,-0.052295685,
  7, 0.171875000, 0.187500000, 0.179687500,-0.012936115,
  8, 0.179687500, 0.187500000, 0.183593750,0.006630838,
  9, 0.179687500, 0.183593750, 0.181640625,-0.003143273,
10, 0.181640625, 0.183593750, 0.182617188,0.001746121,
* n& H+ d; G, v3 b3 w3 c9 M 11, 0.181640625, 0.182617188, 0.182128906,-0.000697991,
12, 0.182128906, 0.182617188, 0.182373047,0.000524211,
13, 0.182128906, 0.182373047, 0.182250977,-0.000086854,


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