, .
( ). y = f(x) [a, b] f(a) = A, f(b) = B. C, A B, C[a, b], f(c) = C.
3.8 ( ): f(x) [a,b]. f [a,b], K, .
3:
16. f(x) 0 ∆ → 0 ( ). : .. .
.., '(x0) x0, .. x, , f(x) 0 (x; y) Ox.
: .
18. f(x) Ә f / Ә x
Ә f / Ә y. ( ), f.
v(x) u(x) xo, (), ( u(x)≠0) , :
(v+-u)` = v`+-u` (vu)` = v`u+vu` (v/u) = (v`u vu`)/u2
19. : f(x) g(x) , , . , limf(x) = limg(x) = 0, g`(x) = 0 . , lim f`(x)/g`(x) ( ), lim f(x)/g(x),
lim f(x)/g(x) = lim f(x)`/g`(x)
:
∞ /∞: , , lim f(x) = lim g(x) = 0 limf(x) = lim g(x) = ∞.
0* ∞ ∞ - ∞ 0\0 ∞ \∞.
17. x, .
. x, (1), , limD x 0D y = 0, .
|
|
, . 4.
. X, . ( ), .
20. () .
1) - , . f`(x)> = 0
2) - , f`(x)< =0.
1) . , - .
2) . , - .
21.: , - y=f(x) . 0 , f`(x0)= 0
, , .
- , , .
: . f(x) , 0 , f`(x) = 0 , f(x0) f(x),
- f(x) x=x0, + .0
- f(x) =0 , + . x0.
- f(x) . x0 f`(x) = 0, f``(x) 0, . x0 - , :
- f``(x) 0, -
- f``(x) 0, - .
22. 1)- y=f(x) () , x1,2 :
f(x1 +2)/2< = f(x1)+ f(x2)/2
2) ( ) , x1,2, , f(x1+2)/2 > =(f (x1)+f (2))/2
: - () , . , .
():
() , - () .
: - X, , f``(x) >= 0 (f``(x)<=0)
23. - , , .
, .
: f`` , .. f``(x)= 0
|
|
: f``(x) x2 , x2 . .
- . - , . .
:
- y = f(x) , , (, f(x)) . .
24. y=f (x) x0 ∆ x : dy = f`(x0) ∆x
:
: df(x) = f`(x)*dx
25. d : ,
df(x) = f`(x) dx
:
v = f(x) u = g(x) . . , . .
, :
d c = 0;
d(c u(x)) = c d u(x);
d(u(x) v(x)) = d u(x) d v(x);
d(u(x) v(x)) = v(x) d u(x) + u(x)d v(x);
d(u(x) / v(x)) = (v(x) d u(x) - u(x) d v(x)) / v2(x).
.
4:
. F(x) f(x) X R, F'(x) = f(x).
f(x), X, f(x) X f(x)dx.
F(x) - f(x),
f(x)dx = F(x)+C.
:
dF(x) = F(x)+C.
dF(x) = F'(x)dx = f(x)dx = F(x)+C.
d f(x)dx = f(x)dx.
d f(x)dx = d(F(x)+C) = dF(x) = F'(x)dx = f(x)dx.
f1(x), f2(x) , f1(x)+f2(x) ,
(f1(x)+f2 (x))dx = f1(x)dx+ f2(x)dx.
f(x) k , kf(x) , k 0
kf(x)dx = k f(x)dx.
:
. .
15 ( ). x = f (t) T, X - , f(x). , f(x) X, T f(x)dx = f(f (t))f' (t)dt. (13)
. F(x) f(x) X, F' (x) = f(x). ,
(F(f (t)))' = F'x(f(t))f '(t) = f(f(t))f '(t).
,
f(f (t))f'(t)dt=F(f(t))+C.
f(x)dx = F(x)+C
:
. , , , , , .
.
, f(x)dx u(x) d(v(x)) - v(x). v(x) ( ) d(u(x)) - u(x). . , .
|
|
33. ba∫ f(x)dx (a,b)
ba∫ f(x)dx = f(b) f(a) -.
ba∫f(x) dx = ∫f(x)dx |ba : ,
.
34. :
I. -:
1) .
ba∫ f(x)dx = ba∫f(t)dt
2)a∫ f(x)dx = 0
3) . .
ba∫f(x)dx = - ab∫ f(x)dx