P(x) = a0xn + a1xn 1 + a2xn 2 + + an 1x + an,
n , a0, a1,, an , .
P(x) = 0, P(x) , .
P1(x) / Q1(x) + P2(x) / Q2(x) + + Pm(x) / Qm(x) = 0,
P1(x), P2(x), ,Pm(x), Q1(x), Q2(x), , Qm(x) , .
P (x) / Q (x) = 0, P (x) Q (x) (Q (x) ¹ 0), P (x) = 0 , Q (x) ¹ 0.
1.
2x 3 + 4(x 1) = 5.
. , x: 2x 3 + 4x 4 = 5, 2x + 4x = 5 + 4 + 3,
6x = 12, x = 2.
: 2.
, .. , , , , .
1. ( - 1) ( + 1) ( - 2) > 0.
. f() = (-1)( + 1)(-2).
0 1,-1,2; . (. 6), f (x) . , ( ).
(2, -1, 1 2. , > -1, >1, > 2 (. 7). x-1>0, +1>0, - 2 > 0, , f () > 0 ( ). , f (x) > 0.
(1,2). -1, 1, 2. , > -1, > 1, < 2 (. 8), x + 1>0,x-1>0,x-2<0. f(x) <0 ( ). , (1,2) f (x) < 0.
(-1,1). -1, 1 2. , >-1, < 1, <2 (. 9), + 1 > 0, -1 <0, - 2 < 0. f (x) > 0 ( ). , (-1,1) f (x)> 0.
, , (-, -1). -1, 1 2. , x<-1, < 1, <2 (. 10). x - 1 < 0, x + 1 < 0, - 2 < 0, , f (x) < 0 ( ). , (-, -1) f (x) < 0.
|
|
. f (x) , . 11. , f (x) > 0. , . 11, , f (x) > 0 (-1, 1)
: -1 < < 1; > 2.
2. , .
= b, > 0, ≠ 1, . = b, :
. > 0, ≠ 1 1 = 2, 1 = 2.
.
, 1 = 2 , .. 1 < 2 1 = 2. , , 1 < 2. > 1, = 1 < 2; 0 < < 1, 1 > 2. 1 = 2.
.
1.
4 ∙ 2 = 1.
.
22 ∙ 2 = 20 2+2 = 20, + 2 = 0, .. = -2.
. = -2.
> b < b. .
.
1.
3 < 81.
.
3 < 34. 3 > 1, = 3 .
, < 4 3 < 34, ≥ 4 3 ≥ 34.
, < 4 3 < 34 , ≥ 4 , ..
3 < 81 , < 4.
. < 4.
, () , .
log a x = b. | (1) |
1. a > 0, a ≠ 1, (1) b x = ab.
1. :
a) log2 x = 3
a) x = 23 x = 8;
f (x) = log a x:
- .
- - .
- a > 1 (0 < x 1 < x 2 Þ log a x 1 < log a x 2), 0 < a < 1, - (0 < x 1 < x 2 Þ log ax 1 > log a x 2).
- log a 1 = 0 log aa = 1 (a > 0, a ≠ 1).
- a > 1, x Î (0;1) x Î (1;+¥), 0 < a < 1, x Î (0;1) x Î (1;+¥).
- a > 1, , a Î (0;1) - .
4.
log < b log ≥ b. . , .
|
|
1.
lg ( + 1) ≤ 2 (1).
.
1) , + 1 > 0, .. > -1.
2) > -1 (1). 10 , , + 1 > 0 (1) , + 1 ≤ 100 ( 2 = lg 100). , (1)
{ > -1, (2)
{ + 1 ≤ 100,
, , (1) (2) .
3) (2), -1 < ≤ 99.
. -1 < ≤ 99.
5.
:
1) , ;
2) ;
3) ;
4) ;
5) (;);
6) .
:
(1) : =2-9
(2) : 5+14-63=44
: 19=107; =107/19
: =43/19.
: (107/19; 43/19)
.
1. , .
2.
3. .
4. , , , .
5. .