1. . . .
3 : 1) D ( x, f(x)); 2) T, E; 3) , D T.
, , x (- D y (- E. y=f(x), , y .
: 1) ( , -
); 2) ( y = f(x)
,
.); 3) ; 4)
: f: XàY g: Y à X , 1 ≠ x2 è f(x1) ≠ f(x2). y (- f(X) x (- X g(x) f(x) x=f-1(y)
: f(x): X à Y g(y): Y à Z. D(g)=E(f). φ: X à Z: φ=g(f(x))=g o f(x) , .. g, f.
2. . .
: y=f(x) x0. f(x) x0 lim f(x)=A (xà x0), ε>0 δ(ε)>0 , , 0<|x- x0|<δ |f(x)-A| < ε
: f(x) x à ∞, ε>0 (ε)>0 , , |x| > M, |f(x)-A| < ε. , .
: ,
((0-δ); (x0+δ)), ((-ε); (A+ε))
.
: f(x) 0 lim f(x)=A,
lim f(x)=B ( à x0). =, .. .
: . δ
2 , .. δ=min(δ1, δ2) |x-x0|<δ.
|A-B| = |A-f(x)+f(x)-B| = |f(x)-A| + |f(x)-B| <= ε+ε = 2ε è A-B=0, A=B
3. .
: ()- y=f(x) 0, (x0-γ; x0) ((x0; x0+ γ)) γ>0 ε>0 δ= δ(ε)>0 , 0<x0-x< δ (0<x-x0< δ) è |f(x)-A|< ε.
|
|
: A=lim f(x) (xàx0-0) (A=lim f(x) (xàx0+0))
x0: (x0-δ; x0)
: x (- (x0; x0+δ)
: . .
4. (..) (..) . .. .. .. .
α() à x0 (..), lim α()=0 (xàx0).
lim α()/β(x) = 0 (xàx0), α() .. β(x), α()=oβ(x), xàx0.
lim α()/β(x) = C (xàx0, c<∞), α() β(x) .. .
lim α()/β(x) = 1 (xàx0), α() β(x)
α() ~ β(x) àx0.
k, lim α()/(β(x))k = C ≠ 0, α() .. k β(x).
Y=F(x) xàx0, lim F(x)= ∞ (xàx0)
: α =α() .. 0 ( ∞). β=1/ α() .. 0 ( ∞). , β= β() .. 0 ( ∞), α()=1/ β() .. 0 ( ∞).
:
α() 0 .. 0. , ε>0 δ =δ(ε) , 0<|x-x0|< δ è | α()|< ε. =1/ε δ =δ(ε)=δ() , 0<|x-x0|< δ è |β(x)| =
|1/ α()| > 1/ ε = M è β(x) . ..
1 : lim sinx/x = 1 (xà0)
x~sinx~tgx~arcsinx~arctgx~(ex-1)~ln(1+x)
1-cosx~x2/2
ax-1~xlna
..:
1) .. ..
2) ..
3) . , .
5. .
lim f(x)=A (xàx0), lim g(x) = B (xàx0), C- , :
1) , , ..
.
: , . . f(x)=b+α(x) g(x)=c+β(x), α β . , f(x) + g(x)=(b + c) + (α(x) + β(x)).
b + c , α(x) + β(x) ,
|
|
.
2) , :
.
: . , f(x)=b+α(x) g(x)=c+β(x)
fg = (b + α)(c + β) = bc + (bβ + cα + αβ).
bc . bβ + c α + αβ . .
3) , , ..
.
: . , f(x)=b+α(x) g(x)=c+β(x), α, β .
.
, , c2≠0.
4) lim (C*f(x)) (xàx0) = C*A
5) lim C (xàx0) = C
6. .
1) 0 f(x) , f(x)<=A lim f(x)=f0 (xàx0). f0<=A.
:
. lim f(x) (xàx0) = f0 = A+γ (γ-.). ε>0 δ>0 , 0<|x-x0|< δ è |f(x)-f0|<ε.
ε = γ/2>0. , |f(x)-f0|< γ/2 0<|x-x0|< D(γ).
|f(x)-f0|>= γ, .. f(x)<=A, a f0=A+ γ.
:
2) 2 :
(- f(x)<=φ(x)<=g(x) lim f(x) = lim g(x) = A (x (- X). lim φ(x) = A.
3) :
(- f(x)<=φ(x)<=g(x) lim f(x) = , lim g(x) = B.
, A<=B. , lim φ(x) = , A<=C<=B
4) :
f(x) () [A; +∞). A , f(x)<=M (f(x)>=m) x (-[A; +∞). lim f(x) (xà+∞) <= M (lim f(x) (xà+∞) >= m). (-∞; B], B-
5) :
y=f(U(x)) . lim U(x) = U0. lim f(U) (UàU0) = f0. lim f(U(x)) = f0.
7. .
́ ́ , , , . , ́ ́. , .
: f(x) () [A; +∞). A , f(x)<=M (f(x)>=m) x (-[A; +∞). lim f(x) (xà+∞) <= M (lim f(x) (xà+∞) >= m). (-∞; B], B- .
8. .
: f(x): X à Y g(y): Y à Z. D(g)=E(f). φ: X à Z: φ=g(f(x))=g o f(x) , .. g, f.
: y=f(U(x)) . lim U(x) = U0. lim f(U) (UàU0) = f0. lim f(U(x)) = f0.
9. .
1 : lim sinx/x = 1 (xà0)
x~sinx~tgx~arcsinx~arctgx~(ex-1)~ln(1+x)
|
|
1-cosx~x2/2
ax-1~xlna
:
, 1.
. (R = 1).
K , L (1;0). H K OX.
, :
(1)
( SsectOKA OKA)
( : | LA | = tg x)
(1), :
:
sin x:
:
:
1, 1.
10. . .
: n 1, 2,..., n,... xn, x 1, x 2, x 3,..., xn . - { xn }.
{ xn }, ε- N, xn, n>N, ε- .
2 . ,
xn=(1+1/n)n, n (- N, e: lim (1+1/n)n = e (nà ∞).
, x, x, , . :
1. . x : , x.
: ,
.
, . , , :
.
( ) .
2. . − x = t,
.
, x.
11. .. .. . .
α() à x0 (..), lim α()=0 (xàx0).
lim α()/β(x) = 0 (xàx0), α() .. β(x), α()=oβ(x), xàx0.
lim α()/β(x) = C (xàx0, c<∞), α() β(x) .. .
lim α()/β(x) = 1 (xàx0), α() β(x)
α() ~ β(x) àx0.
k, lim α()/(β(x))k = C ≠ 0, α() .. k β(x).
Y=F(x) xàx0, lim F(x)= ∞ (xàx0)
:
lim sinx/x = 1 (xà0), :
x~sinx~tgx~arcsinx~arctgx~(ex-1)~ln(1+x)
1-cosx~x2/2
ax-1~xlna
12. . , , ( , 0) . . .
. y=f(x) x0, : 1) f(x) 0; 2) lim f(x) (xàx0); 3) lim f(x) = f(x0). , .
|
|
. , . . , 0 , , .
:
f(x) g(x) 0.
1) f(x)+-g(x)
2) f(x)*g(x)
3) f(x)/g(x), g(x0) ≠ 0
:
lim (f(x)+-g(x)) (xàx0) = lim f(x) +- lim g(x) = f(x0) +- g(x0)
. f(x) . 0, g(t) . t0=f(x0). g(f(x)) 0. .
. .
13. . .
. , , .
(1 ). lim f(x) (xàx0-) lim f(x) (xà x0+); , . x0
(1 ). f(x) 0, . 0 1
. 0 . 0 2 .
14. , .
1. y=f(x) [a; b]. 1, 2 (- [a;b] , (- [a;b] : m = f(x1) <= f(x) <= f(x2) = M. m M.
: .
2. f(x) (- C[a;b] f(a)*f(b)<0 (.. ). x0 (- (a;b), f(x0) = 0.
3. f(x) (- C[a;b] f(a) ≠ f(b). y* (- [f(a); f(b)], f() < f(b) y* (- [f(b); f(a)], f(b) < f(a) x* (- [a;b]: f(x*)=y*, .. , .
4. f(x) (- C[a;b] m-, M- f(x) [a;b]. * (- [m; M] * (- [a; b] , f(x*)=y*, .. , .
!
15. . . . .
. M . t OS=M . t, .. t=S(t). . .
t , t+∆t (∆t ) 1, 1=S+∆S. , ∆t ∆S=S(t+∆t)-S(t). ∆S/∆t ∆t (V=∆S/∆t). ∆t . ∆t : V=lim ∆S/∆t (∆tà0)
. y=f(x)
x=x0 y=f(x) 0,
. f x =0 = lim ∆f(x)/ ∆x (∆xà0) = lim (f(x)-f(x0))/(x-x0) (xàx0)
. y, y(x), f (x), dy/dx .
. y=f(x) x=a
, y, f(a)
. k=f (a), f (a)=tgα
|
|
. y=f(x) . 0=(x0; f(x0)), : 1) 0; 2) ; 3) . y=y0+f (x0)(x-x0)
. y=f(x) 0 . k = -1/k = -1/f (x0) è y = -1/f (x0)*(x-x0)+y0
16. . . . .
. y=f(x) 0, () .
. , y=f(x) 0 , 0 : ∆y=A*∆x+α(x)*∆x, - , α()-.. . 0
:
α()-.. . 0 è lim α()=0
1) .
y=f(x) . . 0, .. lim ∆y/∆x = f (x0). f (x0) = < ∞. α() = -+∆y/∆x. lim ∆y/∆x = lim (-A+ α()) = -A + lim ∆y/∆x = -A+A = 0. α() .. 0.
2)
0 ∆y = A*∆x + α()*∆x. lim ∆y/∆x = lim (A+ α()) = A+0 = ( ). .. . . 0.
, . . . .
. y=f(x) , .
:
f(x) . . 0 è 1 ^ ∆y=A*∆x+α(x)*∆x. ∆xà0 ∆yà0. .. f(x)àf(x0) xàx0, lim f(x) = lim f(x0)
. , .
(logax)=1/(x*lna)
(lnx)=1/x
17. . , , . . .
1) (U(x)+-V(x)) = U(x)+-V(x)
:
∆xà0. ∆(U+V)= ∆U+∆Vèlim ∆(U+V)/ ∆x (∆xà0) = lim (∆U+∆V)/∆x = lim ∆U/∆x + lim ∆V/∆x = U + V
2) (U(x)*V(x))=U(x)*V(x)+U(x)*V(x)
:
∆xà0. ∆(U*V) = (U+∆U)(V+∆V)-UV = UV+U∆V+V∆U+∆U∆V-UV;
(UV) = lim ∆(UV)/ ∆x = lim (U∆V+V∆U+∆U∆V)/∆x = = V*lim ∆U/∆x + U*lim ∆U/∆x + lim ∆U/∆x * lim ∆V (∆xà.) = VU+UV+U*0.
3) (U(x)/V(x)) = (U(x)*V(x) U(x)*V(x))/V2(x)
. y=f(x) 0, f (x0) ≠ 0. y0=f(x0) x=g(y) (x=f-1(y)). 0 : x(y0) = 1/f (x0) g(y0)=1/f(x0), g-. f.
:
g(x) = lim ∆x/∆y (∆yà0) = lim 1/(∆y/∆x) = 1/lim ∆y/∆x (∆xà0) = 1/f(x0)
. x=φ(t) . . t0 y=f(x) . x0=φ(t0). y(φ(t)) . t0: yt(t0) = fx(x0)* φt(t0)
:
y(t0) = lim (∆y(φ(t)))/∆t (tàt0) = lim (∆y*∆x)/(∆x*∆t) = lim ∆y/∆x * lim ∆x/∆t = yx(x0) * xt(t0)
18. . , , (sin x, tg x).
(C) = 0
(x) = 1
(kx+b) = k
(x2) = 2x
(xn) = n*xn-1
(. x) = 1/(2.x)
(1/x) = - 1/x2
(sinx) = cosx
sinα-sinβ = 2sin((α-β)/2)*cos((α+β)/2)
y=lim (sin(x+∆x)-sinx)/∆x (∆xà0) = lim (2sin(∆x/2)*cos((x+∆x)/2))/2*∆x/2 = cosx
(cosx) = -sinx
(tgx) = 1/cos2x
()
(ctgx) = - 1/sin2x
(logax) = 1/(x*lna)
y = lim (loga(x+∆x)-logax)/∆x (∆xà0) = lim (logax+∆x/x)/∆x = lim loga (1+ ∆x/x)/x*∆x/x = 1/x lim loga (1+∆x/x)x/∆x = 1/x lnae =
(lnx) = 1/x
(ex) = ex
(ax) = ax*lna
y=ax x=logay . yx = 1/xy, .. (ax) = 1/(1/y*lna) = ax*lna
(. n- .) = 1/(n* n- . xn-1)
(|x|)' = x/|x|
(arcsinx) = 1/. 1-x2
(arccosx) = -1/. 1-x2
(arctg) = 1/(1+x2)
(arcctg) = -1/(1+x2)
(1/xc) = - c/xc+1
19. , . .
. F(x; y)=0 (1) . 1. y .
. 2 : 1) x=x(t); 2) y=y(t), t , . yx: tx=1/xt ( ). y=f(x) y=y(t), t=φ(x). : yx=yt*tx. : yx=yt*1/xt, .. yx=yt/xt
. 2 , . n- y=f(x) n-1 , 1 n- . y, yn
20. . . . .
. y=f(x) 0 0 dy = f (x0)dx = f (x0)∆x
. . x=U(t); dx=U(t)dt. y=f(U(t)) dy/dt fuU * Ut è dy = f (U)*U (t)dt =
= f (U)*dU
. y=f(x) 0 , M0(x0; y0), , ∆x. ∆xà0 ∆y≈dy, :
f(x0+∆x) ≈ f(x0)+f (x0) ∆x f(x) ≈ f(0)+f (0)x
.
21. , .
. F(x; y)=0 (1) . 1. y .
. 2 : 1) x=x(t); 2) y=y(t), t , . yx: tx=1/xt ( ). y=f(x) y=y(t), t=φ(x). : yx=yt*tx. : yx=yt*1/xt, .. yx=yt/xt
22. , , . .
0 () . y=f(x), 0 : f(x)>=f(x0) (f(x)<=f(x0)). .
. y=f(x) [a;b] . (a;b) 0 (a; b) f(x). f (x0) = 0.
:
.
. y=f(x) .
(a; b) f(a)=f(b). 1 , f (x0)=0.
:
1 2 , m=f(x1)<=f(x)<=f(x2)=M . x (- [a; b]. x1=a, x2=b è f(a)=f(b)=f(x). m=M f(x)=m=M=const (- [a; b]. 1 x1, x2 . 0.
.
y=f(x) [a; b] . (a; b). , y=g(x) [a; b] . (a; b), g(x) ≠ 0 . : ξ (- (a;b) , (f (b) f (a))/(f(b) - f(a)) = f (ξ)/g(ξ)
. f(x) [a; b] . (a; b). ξ (- (a;b) , f(b) f(a) = f(ξ)(b-a)
:
g(x) = x. ξ (- (a;b) , (f(b)-f(a)) / (b-a) = f (ξ)
:
23. .
. f(x) g(x) . b. .. .. . b lim f (x)/g(x) (xàb). lim f(x)/g(x) (xàb) = lim f (x)/g(x).
:
f(x) g(x) [x0; x], 0. f(x)-f(x0)/g(x)-g(x0) = f (c)/g(c). f(x0) g(x0) = 0 . xà x0 0.
:
1)
2) lim f(x)/g(x) ≠ lim (f(x)/g(x))
3) ,
4) 0/0, / .
24. . . . . 1- 2- . .
. , () .
. (- f (x)>0 (f(x)<0). ()
:
x1, x2 (- X, x1<x2. ξ (- (x1; x2) , f(x2)-f(x1) = f (ξ)(x2-x1). x2>x1 è f(x2)>f(x1)
. 0 y=f(x), δ- 0, ≠ 0 : f(x)<f(x0). . . .
. y=f(x) . . f (x0) = 0.
: .
1 . 0 f(x) f(x) . Uε 0. f (x) 0 <x0 f (x)<0 >x0. 0 .
2 . f(x) , . . 0, .. f (x0) = 0. f (x0)>0, x0 , <0 .
.
1) f (x) .
2) D(y), .
3) .
25. : .
. y=f(x) [A; B] . (a; b). . . f(x) [a; b]
.
1) . , .
2)
3) . .
26. , . . () . .
() (a; b), () .
. () (a; b), () .
. y=f(x) () (a; b), 1, 2 (1<x2) : f((x1+x2)/2) > (f(x1)+f(x2))/2 ( <)
. y=f(x) . (a; b) f (x)>0 (f (x)<0) . f(x) () (a; b)
. 0 y=f(x), .
. f(x) 0 . . . f (x) . 0 f(x).
:
f (x)<0 f (x)>0 . 0. . 0. 0 .