.
, .
.
8. . .
y = kx + b, k . , x 0, .
, y = f (x), y = f (x) [ a; b ]. x 0 ∈ (a; b) , :
y = f (x 0) (x − x 0) + f (x 0)
f (x 0) x 0, f (x 0) .
f (x) x 0, , f ' (x 0) ≠ 0 : |
. .
́ , . , .
:
1. ;
2. ;
3. ;
4. ,
.
.
, .
. f (x), 0 Î (, b), () 0, , f ' (x 0) > 0 (f ' (x 0) < 0).
. f (x) 0 Î (, b),
.
0
,
sign A " ". f ' (x 0) > 0 sign f ' (x 0) = + 1,
sign (f (x 0 + h) − f (x 0)) = sign (h).
f (x 0 − h) < f (x 0) < f (x 0 + h), .
. f (x), 0 Î (, b), () x 0, , 0 f ' (x0) ≥ 0 ( f ' (x0) ≤ 0).
. f (x) 0 Î (, b)
f (x 0 − h) < f (x 0) < f (x 0 + h)
h
.
,
.
.
,
,
.
. f (x) () [ , b ], () .
.
. f (x) [ , b ], Î (, b)
|
|
f ' (x) > 0, (f ' (x) < 0),
f (x) () [ , b ].
. 1 < 2 Î [ , b ]
f (x 2) − f (x 1) = f ' (c)(x 2 − x 1),
Î (x 1; x 2).
sign (f (x 2) − f (x 1)) = sign f ' (c)
f ' (x) > 0 Î (, b) f (x 2) > f (x 1), . .