:
: , P(x) (x a):
P(x) = (x a)Q(x),
(x a), 6 a P(x), . , ,
, , .
5 :
1. :
P(x) = xn, P(a) = an,
xn an .
5
P(x) - P(a) = xn an = (x a)Q(x),
,
(xnan)/(xa)=Q(x), .. , .
(xn an)/(x a) = xn-1 + axn-2 + a2xn-3 + +an-2x + an-1.
2. .
P(x) = x2k, P(a) = a2k.
x2k - a2k P(x) P(a).
P(a) = a2k = (-a)2k = P(-a), .. x2k - a2k = P(x) P(-a).
5
P(x) - P(-a) = (x (- a))Q(x)=( + a)Q(x)
,
x2k a2k = (x + a)Q(x)
(x2k a2k)/(x + a) = Q(x),
.. , .
,
(x2k a2k)/(x + a) = x2k-1 ax2k-2 + +a2k-2x + a2k-1.
3. .
P(x) = x2k+1 - a2k+1 .
x2k+1 - a2k+1 x + a = x (-a)
R = P(-a) = (-a)2k+1 a2k+1 = -2a2k+1
. . 0, , .
4. .
P(x) = x2+1, P(-a) = (-a)2+1 = -2+1,
P(x) P(-a) = x2k+1 + a2k+1 .
5
P(x) - P(-a) = x2k+1 + a2k+1= (x (- a))Q(x)= (x + a)Q(x),
,
(x2k+1 + a2k+1)/(x + a) = Q(x),
.. , .
,
(x2k+1 + a2k+1)/(x + a) = x2k - ax2k-1 + - a2k-1x + a2k.
5. .
P(x) = x2k + a2k .
x2k + a2k x + a = x (-a)
R = P(-a) = (-a)2k + a2k = 2a2k.
. . 0,
|
|
, .
. .
1.
x3 3x2 + 6x 5
x 2.
R = P3 (2) = 23 3*22 + 6*2 5 = 3.
: R = 3.
2.
32x4 64x3 + 8x2 + 36x + 4
2x 1.
1
R=P4(1/2)=32*1/2464*1/23 + 8*1/22+36*1/2+4=
= 2 8 + 2 + 18 + 4 =18.
: R = 18.
3.
a
x4 + ax3 + 3x2 4x 4
x 2?
R = P4 (2) = 16 + 8a + 12 8 4 = 8a +16.
R = 0,
8a + 16 = 0,
a = -2.
: a = -2.
4.
a b
ax3 + bx2 73x + 102
x2 5x + 6 ?
:
x2 5x + 6 = (x 2)(x 3).
x 2 x 3 , x 2 x 3, ,
R1 = P3 (2) = 8a + 4b 146 + 102 =
= 8a + 4b 44 = 0
R2 = P3 (3) = 27a+9b 219 + 102 =
= 27a +9b -117 =0
:
8a + 4b 44 = 0
27a + 9b 117 = 0
2a + b = 11
3a + b = 13
:
a = 2, b = 7.
: a = 2, b = 7.
5.
P(x) = x4 + 4x2 5.
1 P(x), , 2 P(x) (x 1) :
_x4 + 4x2 5 x 1
x4 x3 x3 + x2 + 5x + 5
_ x3 + 4x2 5
x3 x2
_ 5x2 5
5x2 5x
_ 5x 5
5x 5
0
P(x)/(x 1) = x3 + x2 + 5x + 5,
P(x) = (x 1)*(x3 + x2 + 5x + 5).
x3 + x2 + 5x + 5 x = -1 , , 2 x3 + x2 + 5x + 5 (x + 1) :
_x3 + x2 +5x + 5 x + 1
x3 + x2 x2 +5
_5x + 5
5x + 5
0
(x3 + x2 +5x + 5)/(x + 1) = x2 +5,
x3 + x2 +5x + 5 = (x +1)(x2 +5).
P(x) = (x 1)(x +1)(x2 +5).
7 (x2 + 5) , .. , P(x) .
: x4 + 4x2 5 = (x 1)(x +1)(x2 +5).
7.
P(x) = x4 + 324.
P(x) , .. x4 -324, , 7 P(x) .
: .
8.
2
P(x) = x5 - 5x4 + 7x3 2x2 + 4x 8.
: P(x) (x a)k, (x a)k+1 , , a k P(x).
_x5 - 5x4 + 7x3 2x2 + 4x 8 x 2
x5 - 2x4 x4 3x3 + x2 + 4
_-3x4 + 7x3 2x2 + 4x 8
|
|
-3x4 + 6x3
_x3 2x2 + 4x 8
x3 2x2
_4x 8
4x 8
0
_x4 3x3 + x2 + 4 x 2
x4 2x3 x3 x2 x 2
_-x3 + x2 + 4
-x3 +2x2
_-x2 + 4
-x2 + 2x
_-2x + 4
-2x + 4
0
_ x3 x2 x 2 x 2
x3 2x2 x2 + x + 1
_x2 x 2
x2 2x
_x 2
x 2
0
x2 + x + 1 x 2 , .. R=22 + 2 + 1=7.
, P(x)/(x 2)3 = x2 + x + 1, .. 2 3 P(x).
: 2 3 P(x).
9.
, 4 2 -2.
3, P(x) 4 2 2, (x 4)2(x + 2),
P(x)/(x 4)2(x + 2) = Q(x),
.. P(x) = (x 4)2(x + 2)Q(x) =
= (x2 8x +16)(x + 2)Q(x) =
= (x3 8x2 + 16x +2x2 16x + 32)Q(x) =
= (x3 6x2 + 32)Q(x).
(x3 6x2 + 32) - , P(x) , , Q(x) .
Q(x) = 1, P(x) = x3 6x2 + 32.
: x3 6x2 + 32.
9.
a b , -2 P(x) = x5 + ax2 + bx + 1, .
-2 P(x) , 3 P(x) (x + 2)2 (R = 0)
(x + 2)2 = x2 + 4x + 4
_x5 + ax2 + bx + 1 x2 + 4x + 4
x5 + 4x4 + 4x3 x3 4x2 + 12x (a + 32)
_ -4x44x3ax2+bx+1
-4x4 16x3 16x2
_ 12x3 + (16 a)x2 + bx + 1
12x3 +48x2 + 48x
_ -(a + 32)x2 + (b 48)x + 1
-(a + 32)x2 4(a + 32)x 4(a + 32)
(4a +b 48 + 128)x + 4a + 129
R = (4a +b 48 + 128)x + 4a + 129 =
= (4a +b + 80)x + 4a + 129
R = 0,
(4a +b + 80)x + 4a + 129 = 0 x.
,
4a +b + 80 = 0,
4a + 129 = 0
:
4a +b + 80 = 0 a = -32,25
4a + 129 = 0 b = 49
: a = -32,25, b = 49.
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