1: f (x)= A 0 xn + A 1 xn -1+ A 2 xn -2++ An -1 x + An, , () ; . A 0, A 1,..., ; , .
2: , .
1 ( ): f (x) - , f (a).
: , . . f (a)=0, f (x) - , ,
f (x)=(x - a) f 1(x), f 1(x) .
:
: f (x)= x 3-2 x 2+3 x -2
: 1; 2.
x =1 , f (1)=0.
x 3-2 x 2+3 x -2 | x -1
x 3- x 2 x 2- x +2
- x 2+3 x -2
- x 2+ x
2 x -2
2 x -2
f (x)= x 3-2 x 2+3 x -2=(x -1)(x 2- x +2)
.
3: ( ), , , , .
4: Q (x) = 0, Q (x)- n, .
, Q (x) = 0 , Q (x).
: ?
: , , .
. :
2: ( ). f(x) , . .
3: n - n - , .
Q (x) :
Q (x)= A 0(x - 1)(x - 2)(x - n),
A 0 Q (x), 1, 2, , n - Q (x)=0.
(x - 1), (x - 2), , (x - n) .
- .
:
n - | 0 n + 1 n -1++ n -2 2+ n -1 + n n + n -1++ U 2+ V + W | |
4+ 3+ 2+ D + E | - 4-2 3+3 2+8, =-1; =-2; =3; D =0; E =8; | |
3+ 2+ + D | 2 3- 2+4 , =2; =-1; =4; D =0; | |
2+ + | - 2+4 -3, =-1; =4; =-3; | |
+ | +8, =1; =8; | |
1, =1. |
|
|
.
-
Q (x)= A 0(x - 1)(x - 2)(x - n)
, , :
Q (x)= A 0(x - 1) k 1(x - 2) k 2(x - m) k m, k 1+ k 2++ km = n m £ n.
= 1 k 1 k 1- , = 2 k2 ..
:
3 5( +2)3( -1)2( -2)2( +5)
=0 ; =-2 ; =1 ;
=2 ; =-5 .
= k, , k .
.
1: - ( ).
2+ bx + c:
D >0 ;
D =0 ;
D <0 () .