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二分法是计算机求解方程的常用算法,很容易在matlab中实现。2 U+ p! V, g, O% q1 l( R. Q, Y! W, F) d
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%计算f(x)= 0的近似解,容差为tol
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fuction xc = bisec(f,a,b,tol)
; g. Z4 g( J5 k% t8 hif sign(f(a))*sign(f(b)) >= 0 @6 e a8 i/ b2 [2 |
error('f(a)f(b)<0 not satisfied!')" C8 c6 O7 K2 w- G' _+ [' i
end
- S8 B" b8 u/ U5 z6 `& @& C: m( ufa = f(a);# V* A) |3 s6 E: C& p4 W+ v
fb = f(b);
3 ]" i8 S. j' {while (b-a)/2 > tol1 B7 C, m+ }* U" t( o
c = (a+b)/2;
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if fc == 0
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end
}: c( \# V7 f X# j5 n if sign(fa)*sign(fb)<0
' X% R9 x' V3 \. F+ w) [ b=c;fb = fc;
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a = c;fa = fc;8 R+ o/ F1 k; H' @1 _3 h- f
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end) D$ ~0 g4 o( y
xc = (a+b)/2
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+ B: w4 d9 _$ V* b6 N* `在matlab中首先要在命令行中键入:
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- }& \, ^" N1 P% c; G f = @(x) x^3+x-1
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