Bairstow method
ġؼ
1.Bairstow method
P(x) DZٰ ϴ ϴ
2İ
Ÿ Ѵ.
( , )
p(x) = a0xn + a1xn-1++ an-xx +an (1)
,(,a0 0)̶ ϰ,
p(x) 2 x2-rx-s
p(x)=(x2-rx-s)Q(x)+u(x-r)+v (2)
⼭ Q(x) n-2 ̰,
u(x-r)+v p(x) x2-rx-s ̴.
̶,
Q(x)=bnxn-2+bn-xxn-3+.+b4x2+b3x+b2 ̶ ϰ,
(2) Ͽ Ϲȭѽ (3)̶ ϰ, ̶ Q(x) bk (1) (2) xk Ͽ ´.
̷ ȭ ̿Ͽ ظ ϴ bairstow method Ѵ.
.
ᱹ Ѵ.
To find the couple roots of a poly
find the guadratic factors.
find the zero of the guadratic factor
by why guadratic factor formal.
2. Matlab ̿
3.8 f(x)=x3+3x2+5x-1 DZ ٻ 0.1795090246̡()
|
[C(n-1,3) C(n-2,3); C(n,3) C(n-1,3)]
[C(n,2) ;C(n+1,2)];
%Newton Method̴
u=B(1), v=B(2)
%B=[u v] u=B(1), v=B(2)̴
fprintf(press any key continue \n);
% press any key continue ض
pause
% ȣ̴
end
root=roots([1 u v])
% [1 u v] ̷ ض.
k a_k b_k c_k
0 1.00000 1.00000000000000 1.00000000000000
1 3.00000 -0.17950902460294 -3.359xxxxxxxxxxx
2 5.00000 0.00000000000015 5.10927763753183
3 -1.00000 -0.00000000000035 0.00000000000000
u =
-3.17950902460292
v =
-5.57075056372264
press any key to contionue
root =
-1.58975451230146 + 1.74454325092266i
-1.58975451230146 - 1.74454325092266i
ġؼ (-迵, )
ġؼ matlab (-)