A elementar ˘ a • Limite de ¸siruri elementare
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- Limite de funct¸ii elementare
- Propriet˘at¸i ale funct¸iei exponent¸iale
- Propriet˘at¸i ale funct¸iei sinus ¸si cosinus
- Seria armonic˘a generalizat˘a
Not¸iuni introductive Lect. dr. Lucian Maticiuc ANALIZ ˘ A ELEMENTAR ˘ A • Limite de ¸siruri elementare: 1) lim
n→∞ q n = 0, dac˘a |q| < 1, 1, dac˘a q = 1, ∞, dac˘a q > 1, nu exist˘a, dac˘a q ≤ −1 2) lim n→∞ a 1 n p + a 2 n p−1 + a 3 n p−2 + · · · a p n + a
p+1 = ∞ , dac˘a a 1 > 0,
−∞ , dac˘a a 1
, p ∈ N ∗ (limit˘a dintr-un polinom de grad p ˆın variabila n) 3) lim
n→∞ a 1 n p + a 2 n p−1 + a 3 n p−2 + · · · a p n + a
p+1 b 1 n q + b 2 n q−1 + b 3 n q−2 + · · · b q n + b
q+1 = ∞ a 1 b 1 , dac˘a p > q, a 1
1 , dac˘a p = q, 0 , dac˘a p < q , p, q ∈ N (limit˘a dintr-o fract¸ie de polinoame ˆın variabila n) 4) lim
n→∞ sin x
n x n = 1, unde x
n → 0
5) lim
n→∞ tg x
n x n = 1, unde x
n → 0
6) lim
n→∞ 1 +
1 x n x n = e, unde x n → ∞, 7) lim
n→∞ (1 + x
n ) 1 x n = e, unde x n → 0 8) lim
n→∞ e n n p = ∞ (p ∈ N) 9) lim
n→∞ ln n
n p = 0 (p ∈ N ∗ ) 10) lim n→∞
a x n − 1 x n = ln a, unde x
n → 0
11) lim
n→∞ ln (1 + x n )
n = 1,
unde x n → 0 12) lim
n→∞ n √ n = 1, ( n √ n) n este s¸ir descresc˘ator 1 Lucian Maticiuc Not¸iuni introductive Lect. dr. Lucian Maticiuc • Limite de funct¸ii elementare: 1) lim x→0 x>0
1 x = 1 0 + = +∞ 2) lim x→0 x<0
1 x = 1 0 − = −∞ 3) lim x→∞ ln x = ln ∞ = +∞ 4) lim
x→0 x>0
ln x = ln 0 + = −∞ 5) lim
x→∞ e x = e ∞ = +∞ 6) lim
x→−∞ e x = e −∞ = 1 e ∞ = 0 7) lim x→∞ a x = a ∞ = +∞, dac˘a a > 1 0, dac˘a 0 < a < 1 8) lim
x→∞ x a = ∞ a = +∞, dac˘a a > 0 0, dac˘a a < 0 9) lim
x→0 sin x
x = 1
10) lim
x→0 tg x
x = 1
11) lim
x→∞ 1 +
1 x x = e 12)
lim x→0
(1 + x) 1 x = e 13)
lim x→∞
e x x p = +∞
(p ∈ R) 14)
lim x→∞
ln x x p = 0 (p ∈ R ∗ )
lim x→0
a x − 1 x = ln a
16) lim
x→0 ln (1 + x) x = 1
17) lim
x→∞ a 1 x p + a 2 x p−1 + · · · + a p x + a p+1 b 1 x q + b 2 x q−1 + · · · + b q x + b q+1 = a 1 b 1 , dac˘a p = q 0, dac˘a p < q +∞, dac˘a p > q 2
Not¸iuni introductive Lect. dr. Lucian Maticiuc • Propriet˘at¸i ale funct¸iei exponent¸iale: 1) e x · e
y = e
x+y , e x−y = e x e y 2) e x ≥ 1, ∀x ≥ 0, e x < 1, ∀x < 0, e 0 = 1 3) Funct¸ia x → e x este cresc˘atoare ∀x ∈ R propriet˘at¸i ale funct¸iei logaritm: 4) ln (xy) = ln x + ln y, ln x y = ln x − ln y, ln 1 x = − ln x
5) ln x ≥ 0, ∀x ≥ 1, ln x < 0, ∀0 < x < 1, ln 1 = 0, ln e = 1 6) Funct¸ia x → ln x este cresc˘atoare ∀x > 0 s¸i 7) e ln x = x = ln e x , ∀x > 0
• Propriet˘at¸i ale funct¸iei sinus ¸si cosinus: 1) cos (2nπ) = 1, cos (2n + 1) π 2 = 0, cos ((2n + 1) π) = −1, ∀n ∈ Z 2) sin (nπ) = 0, sin (2n + 1) π 2 = (−1) n , ∀n ∈ Z 3) sin (2nπ + x) = sin x, cos (2nπ + x) = cos x, ∀n ∈ Z, x ∈ R (adic˘a funct¸iile sin s¸i cos sunt periodice) 4) funct¸iile periodice nu au limt˘a la infinit (deci nu ∃ sin ∞ def = lim
x→∞ sin x
) 5) |sin x| ≤ 1, |cos x| ≤ 1, ∀x ∈ R 6) exist˘a limita lim x→∞ sin x
x = lim
x→∞ 1/x
→0 sin x
m˘ arginit˘
a = 0
3 Lucian Maticiuc Not¸iuni introductive Lect. dr. Lucian Maticiuc • Seria armonic˘a generalizat˘a ∞ n=1 1 n p = convergent˘a , dac˘a p > 1 divergent˘a , dac˘a p ≤ 1 • Seria geometric˘a ∞ n=1 q n = convergent˘a , dac˘a |q| < 1 divergent˘a , dac˘a |q| ≥ 1 • Binomul lui Newton (a + b) p
p + C
1 p a p−1 b + C
2 p a p−2 b 2 + · · · + C p−1
p ab p−1 + b p , unde p ∈ N ∗ • Suma primilor n termeni ai unei progresii geometrice 1 + q + q 2 + q 3 + · · · + q n =
n+1 1 − q
, ∀q = 1 • Suma primelor n numere naturale 1 + 2 + 3 + · · · + n = n (n + 1) 2 s¸i suma p˘atratelor primelor n numere naturale 1 2 + 2 2 + 3
2 + · · · + n 2 =
6 • Partea ˆıntreag˘a [a] ∈ Z este cel mai mare ˆıntreg din stˆanga num˘arului real a, adic˘a [a] ≤ a < [a] + 1, ∀a ∈ R De asemenea, partea ˆıntreag˘a verific˘a s¸i a − 1 < [a] ≤ a, ∀a ∈ R • Dac˘a avem ecuat¸ia ax 2
cu r˘ad˘acinile x 1 , x 2 , atunci are loc descompunerea ax 2
1 ) (x − x
2 ) 4 Lucian Maticiuc Not¸iuni introductive Lect. dr. Lucian Maticiuc Derivatele funct¸iilor elementare 1. c = 0 2. x = 1
3. (x n ) = nx n−1
, n ∈ N 4. (x a ) = ax
a−1 , a ∈ R + 5.
√ x) =
1 2 √ x (obt¸inut˘a ˆın particular pentru a = 1/2) 6. 1
= −1 x 2 (obt¸inut˘a ˆın particular pentru a = −1) 7. (a
) = a x ln a , a ∈ R + , a = 1
8. (e x ) = e x (obt¸inut˘a ˆın particular pentru a = e) 9. (ln x) =
1 x 10. (sin x) = cos x 11.
(cos x) = − sin x 12.
(tg x) = 1 cos 2 x 13. (ctg x) = −1 sin 2 x 14. (arcsin x) = 1 √ 1 − x 2 15. (arccos x) = −1 √ 1 − x 2 16. (arctg x) = 1 1 + x 2 17.
(arcctg x) = −1 1 + x 2 18.
(sh x) = ch x , unde sh x def =
x − e
−x 2 este sinusul hiperbolic 19. (ch x) = sh x unde ch x def
= e x + e −x 2 este cosinusul hiperbolic 5
Maticiuc Not¸iuni introductive Lect. dr. Lucian Maticiuc Derivatele funct¸iilor compuse 1. (u n ) = nu
n−1 · u , n ∈ N 2. (u
) = au a−1
· u , a ∈ R + 3. ( √ u) = 1 2 √ u · u
(obt¸inut˘a ˆın particular pentru a = 1/2) 4. 1 u = −1 u 2 · u (obt¸inut˘a ˆın particular pentru a = −1) 5. (a u ) = a
u ln a · u , a ∈ R + , a = 1
6. (e u ) = e u · u (obt¸inut˘a ˆın particular pentru a = e) 7. (ln u) = 1 u · u 8. (sin u) = cos u · u 9. (cos u) = − sin u · u 10. (tg u) =
1 cos
2 u · u 11. (ctg u) = −1 sin
2 u · u 12. (arcsin u) = 1 √
2 · u
13. (arccos u) = −1 √
2 · u
14. (arctg u) = 1 1 + u
2 · u
15. (arcctg u) = −1 1 + u
2 · u
16. (sh u) =
e u − e −u 2 = ch u · u 17. (ch u) =
e u + e −u 2 = sh u · u Operat¸ii cu funct¸ii derivabile 1. (f + g) (x) = f (x) + g (x) 2. (C · f ) (x) = C · f (x) 3. (f · g) (x) = f (x) · g (x) + f (x) · g (x) 4. 1 g (x) = −1 g 2 (x)
g (x) 5. f g (x) =
f (x) · g (x) − f (x) · g (x) g 2 (x) 6
Maticiuc Not¸iuni introductive Lect. dr. Lucian Maticiuc Integrale nedefinite 1. dx = x + C 2. x α dx = x α+1 α + 1 + C , α ∈ R , α = −1 3. 1 x dx = ln |x| + C 4. 1
2 + a
2 dx =
1 a arctg x a + C , a = 0 5. 1 x 2 − a 2 dx =
1 2a ln x − a x + a
+ C , a = 0
6. 1 √ x 2 ± a 2 dx = ln x + x 2
2 + C
, a = 0 7. 1 √ a 2 − x 2 dx = arcsin x a + C , a > 0 8. a x dx =
a x ln a + C , a > 0, a = 1 , e x
x + C
9. sin xdx = − cos x + C 10. cos xdx = sin x + C 11. 1 cos 2 x dx = tg x + C 12. 1 sin 2 x dx = − ctg x + C 13. 1 sin x dx = ln tg x 2 + C 14.
1 cos x
dx = ln tg x 2 + π 4 + C 15.
tg xdx = − ln |cos x| + C 16.
ctg xdx = ln |sin x| + C Metode de calcul 1. Formula de integrare prin p˘art¸i pentru integrala definit˘a b a f (x) g (x) dx = [f (x) g (x)] b a − b a f (x) g (x) dx. 2. Prima metod˘a de schimbare de variabil˘a pentru integrala definit˘a: pentru a calcula b a
se noteaz˘a y not
= u (x) deci dy = u (x) dx s¸i are loc b a
u(b) u(a)
f (y) dy = F (y) u(b)
u(a) = F (u (b)) − F (u (a)) . 7 Lucian Maticiuc Download 102 Kb. Do'stlaringiz bilan baham: |
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