Ta lista szeregów matematycznych zawiera wzory na sumy skończone i nieskończone. Może być używany w połączeniu z innymi narzędziami do oceny sum.
Sumy potęg
Zobacz wzór Faulhabera .
∑
k =
0
m
k
n - 1
=
b
n
( m + 1 ) -
b
n
n
{\ Displaystyle \ suma _ {k = 0} ^ {m} k ^ {n-1} = {\ Frac {B_ {n} }(m+1)-B_{n}}{n}}}
Kilka pierwszych wartości to:
∑
k = 1
m
k =
m ( m + 1 )
2
{\ Displaystyle \ suma _ {k = 1} ^ {m} k = {\ Frac {m (m + 1)} {2}}}
∑
k = 1
m
k
2
=
m ( m + 1 ) ( 2 m + 1 )
6
=
m
3
3
+
m
2
2
+
m 6
{\ Displaystyle \ suma _ {k = 1} ^ {m} k ^ { 2}={\frac {m(m+1)(2m+1)}{6}}={\frac {m^{3}}{3}}+{\frac {m^{2}}{ 2}}+{\frac {m}{6}}}
∑
k = 1
m
k
3
=
[
m ( m + 1 )
2
]
2
=
m
4
4
+
m
3
2
+
m
2
4
{\ Displaystyle \ suma _ {k = 1} ^ {m} k ^ {3} =\left[{\frac {m(m+1)}{2}}\right]^{2}={\frac {m^{4}}{4}}+{\frac {m^{3 }}{2}}+{\frac {m^{2}}{4}}}
Zobacz stałe zeta .
ζ ( 2 n ) =
∑
k = 1
∞
1
k
2 n
= ( - 1
)
n + 1
b
2 n
( 2 π
)
2 n
2 ( 2 n ) !
{\ Displaystyle \ zeta (2n) = \ suma _ {k = 1} ^ {\ infty} {\ Frac {1} {k ^ {2n}}} = (-1) ^ {n + 1} {\ frac {B_{2n}(2\pi)^{2n}}{2(2n)!}}}
Kilka pierwszych wartości to:
ζ ( 2 ) =
∑
k = 1
∞
1
k
2
=
π
2
6
{\ Displaystyle \ zeta (2) = \ suma _ {k = 1} ^ {\ infty} {\ Frac {1} {k ^ {2} }}}={\frac {\pi ^{2}}{6}}}
( problem bazylejski )
ζ ( 4 ) =
∑
k = 1
∞
1
k
4
=
π
4
90
{\ Displaystyle \ zeta (4) = \ suma _ {k = 1} ^ {\ infty} {\ Frac {1} {k ^ {4 }}}={\frac {\pi ^{4}}{90}}}
ζ ( 6 ) =
∑
k = 1
∞
1
k
6
=
π
6
945
{\ Displaystyle \ zeta (6) = \ suma _ {k = 1} ^ {\ infty} {\ Frac {1} {k ^ {6 }}}={\frac {\pi ^{6}}{945}}}
Serie mocy
Polilogarytmy niskiego rzędu
Sumy skończone:
∑
k = m
n
z
k
=
z
m
-
z
n + 1
1 - z
{\ Displaystyle \ suma _ {k = m} ^ {n} z ^ {k} = {\ Frac {z ^ {m} -z ^{n+1}}{1-z}}}
, ( szereg geometryczny )
∑
k =
0
n
z
k
=
1 -
z
n + 1
1 - z
{\ Displaystyle \ suma _ {k = 0} ^ {n} z ^ {k} = {\ Frac {1-z ^ {n + 1} }{1-z}}}
∑
k = 1
n
z
k
=
1 -
z
n + 1
1 - z
- 1 =
z -
z
n + 1
1 - z
{\ Displaystyle \ suma _ {k = 1} ^ {n} z ^ {k} = {\frac {1-z^{n+1}}{1-z}}-1={\frac {zz^{n+1}}{1-z}}}
∑
k = 1
n
k
z
k
= z
1 - ( n + 1 )
z
n
+ n
z
n + 1
( 1 - z
)
2
{\ Displaystyle \ suma _ {k = 1} ^ {n} kz ^ {k }=z{\frac {1-(n+1)z^{n}+nz^{n+1}}{(1-z)^{2}}}}
∑
k = 1
n
k
2
z
k
= z
1 + z - ( n + 1
)
2
z
n
+ ( 2
n
2
+ 2 n - 1 )
z
n + 1
-
n
2
z
n + 2
( 1 - z
)
3
{\ Displaystyle \ suma _ {k = 1} ^ {n} k ^ {2} z ^ {k} = z {\ Frac {1 + z- (n + 1) ^ {2} z ^ {n} + (2n^{2}+2n-1)z^{n+1}-n^{2}z^{n+2}}{(1-z)^{3}}}}
∑
k = 1
n
k
m
z
k
=
(
z
re re
z )
m
1
- z
n
+ 1 1
- z {
\ Displaystyle \ suma _ {k = 1} ^ {n} k ^ {m} z ^ {k }=\left(z{\frac {d}{dz}}\right)^{m}{\frac {1-z^{n+1}}{1-z}}}
Sumy nieskończone, ważne dla
|
z
|
< 1
{\ Displaystyle | z| <1}
(patrz polilogarytm ):
Li
n
( z ) =
∑
k = 1
∞
z
k
k
n
{\ Displaystyle \ nazwa operatora {Li} _ {n} (z) = \ suma _ {k = 1} ^ {\ infty} {\ Frac {z ^{k}}{k^{n}}}}
Poniższa właściwość jest przydatna do rekurencyjnego obliczania polilogarytmów o niskim rzędzie całkowitym w postaci zamkniętej :
re re
z
Li
n
( z ) = Li
n
- 1
( z ) z
{
\ Displaystyle {\ Frac {\ operatorname {d}} {\ operatorname {d} z}} \ operatorname {Li} _ {n} (z) = {\ frac {\ nazwa operatora {Li} _ {n-1} (z)} {z}}}
Li
1
( z ) =
∑
k = 1
∞
z
k
k
= - ln ( 1 - z )
{\ Displaystyle \ operatorname {Li} _ {1} (z) = \ suma _ {k = 1} ^ { \infty}{\frac {z^{k}}{k}}=-\ln(1-z)}
Li
0
( z ) =
∑
k = 1
∞
z
k
=
z
1 - z
{\ Displaystyle \ nazwa operatora {Li} _ {0} (z) = \ suma _ {k = 1} ^ {\ infty} z ^ { k}={\frac {z}{1-z}}}
Li
- 1
( z ) =
∑
k = 1
∞
k
z
k
=
z
( 1 - z
)
2
{\ Displaystyle \ nazwa operatora {Li} _ {- 1} (z) = \ suma _ {k = 1} ^ {\infty}kz^{k}={\frac {z}{(1-z)^{2}}}}
Li
- 2
( z ) =
∑
k = 1
∞
k
2
z
k
=
z ( 1 + z )
( 1 - z
)
3
{\ Displaystyle \ nazwa operatora {Li} _ {- 2} (z) = \ suma _ {k=1}^{\infty}k^{2}z^{k}={\frac {z(1+z)}{(1-z)^{3}}}}
li
- 3
( z ) =
∑
k = 1
∞
k
3
z
k
=
z ( 1 + 4 z +
z
2
)
( 1 - z
)
4
{\ Displaystyle \ nazwa operatora {Li} _ {- 3} (z) =\suma _{k=1}^{\infty}k^{3}z^{k}={\frac {z(1+4z+z^{2})}{(1-z)^{ 4}}}}
li
- 4
( z ) =
∑
k = 1
∞
k
4
z
k
=
z ( 1 + z ) ( 1 + 10 z +
z
2
)
( 1 - z
)
5
{\ Displaystyle \ nazwa operatora {Li} _ {- 4}(z)=\suma _{k=1}^{\infty}k^{4}z^{k}={\frac {z(1+z)(1+10z+z^{2} )}{(1-z)^{5}}}}
Funkcja wykładnicza
∑
k =
0
∞
z
k
k !
=
mi
z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {z ^ {k}} {k!}} = e ^ {z}}
∑
k =
0
∞
k
z
k
k !
= z
mi
z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} k {\ Frac {z ^ {k}} {k!}} = ze ^ {z}} (por. średnia
rozkładu Poissona )
∑
k =
0
∞
k
2
z
k
k !
= ( z +
z
2
)
mi
z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} k ^ {2} {\ frac {z ^ {k}}} {k!}} = (z + z ^{2})e^{z}}
(por. drugi moment rozkładu Poissona)
∑
k =
0
∞
k
3
z
k
k !
= ( z + 3
z
2
+
z
3
)
mi
z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} k ^ {3} {\ Frac {z ^ {k}} {k!}} = (z+3z^{2}+z^{3})e^{z}}
∑
k =
0
∞
k
4
z
k
k !
= ( z + 7
z
2
+ 6
z
3
+
z
4
)
mi
z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} k ^ {4} {\ Frac {z ^ {k}}} {k !}}=(z+7z^{2}+6z^{3}+z^{4})e^{z}}
∑
k =
0
∞
k
n
z
k
k !
= z
re
re z
∑
k =
0
∞
k
n - 1
z
k
k !
=
mi
z
T
n
( z )
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} k ^ {n} {\ Frac {z ^ {k}}} {k!}} = z {\ frac { d}{dz}}\suma _{k=0}^{\infty}k^{n-1}{\frac {z^{k}}{k!}}\,\!=e^{z }T_{n}(z)}
gdzie
T
n
( z )
{\ Displaystyle T_ {n} (z)}
to wielomiany Toucharda .
Funkcje trygonometryczne, odwrotne trygonometryczne, hiperboliczne i odwrotne funkcje hiperboliczne
∑
k =
0
∞
( - 1
)
k
z
2 k + 1
( 2 k + 1 ) !
= grzech z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k} z ^ {2k + 1}} {(2k + 1)!}} = \sin z}
∑
k =
0
∞
z
2 k + 1
( 2 k + 1 ) !
= sinh z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {z ^ {2k + 1}} {(2k + 1)!}} = \ sinh z}
∑
k =
0
∞
( - 1
)
k
z
2 k
( 2 k ) !
= sałata z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k} z ^ {2k}} {(2k)!}} = \ cos z}
∑
k =
0
∞
z
2 k
( 2 k ) !
= cosh z
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {z ^ {2k}} {(2k)!}} = \ cosh z}
∑
k = 1
∞
( - 1
)
k - 1
(
2
2 k
- 1 )
2
2 k
b
2 k
z
2 k - 1
( 2 k ) !
= dębnik z ,
|
z
|
<
π 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1) ^ {k-1} (2 ^ {2k} -1) 2 ^ {2k} B_ {2k} z ^ {2k-1}}{(2k)!}}=\tan z,|z|<{\frac {\pi }{2}}}
∑
k = 1
∞
(
2
2 k
- 1 )
2
2 k
b
2 k
z
2 k - 1
( 2 k ) !
= tanh z ,
|
z
|
<
π 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(2 ^ {2k} -1) 2 ^ {2k} B_ {2k} z ^ {2k-1}}} (2k)!}}=\tanh z,|z|<{\frac {\pi }{2}}}
∑
k =
0
∞
( - 1
)
k
2
2 k
b
2 k
z
2 k - 1
( 2 k ) !
= łóżko polowe z ,
|
z
|
< π
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k} 2 ^ {2k} B_ {2k} z ^ {2k-1}} {(2k )!}}=\cot z,|z|<\pi }
∑
k =
0
∞
2
2 k
b
2 k
z
2 k - 1
( 2 k ) !
= cot z ,
|
z
|
< π
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {2 ^ {2k} B_ {2k} z ^ {2k-1}} {(2k)!}} = \ coth z ,|z|<\pi }
∑
k =
0
∞
( - 1
)
k - 1
(
2
2 k
- 2 )
b
2 k
z
2 k - 1
( 2 k ) !
= csc z ,
|
z
|
< π
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k-1} (2 ^ {2k} -2) B_ {2k} z ^ {2k- 1}}{(2k)!}}=\csc z,|z|<\pi }
∑
k =
0
∞
- (
2
2 k
- 2 )
b
2 k
z
2 k - 1
( 2 k ) !
= csch z ,
|
z
|
< π
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {- (2 ^ {2k} -2) B_ {2k} z ^ {2k-1}} {(2k)!} }=\nazwa_operatora {csch} z,|z|<\pi }
∑
k =
0
∞
( - 1
)
k
mi
2 k
z
2 k
( 2 k ) !
= sech z ,
|
z
|
<
π 2
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k} E_ {2k} z ^ {2k}} {(2k)!}} = \ operatorname {sech} z,|z|<{\frac {\pi }{2}}}
∑
k =
0
∞
mi
2 k
z
2 k
( 2 k ) !
= sek z ,
|
z
|
<
π 2
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {E_ {2k} z ^ {2k}} {(2k)!}} = \ s z, | z | <{{{ \frac {\pi }{2}}}
∑
k = 1
∞
( - 1
)
k - 1
z
2 k
( 2 k ) !
= ver z
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1) ^ {k-1} z ^ {2k}} {(2k)!}} = \ nazwa operatora {wers} z}
( werset )
∑
k = 1
∞
( - 1
)
k - 1
z
2 k
2 ( 2 k ) !
= hav z
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1) ^ {k-1} z ^ {2k}} {2 (2k)!}} = \ nazwa operatora {hav} z}
( haversine )
∑
k =
0
∞
( 2 k ) !
z
2 k + 1
2
2 k
( k !
)
2
( 2 k + 1 )
= arcsin z ,
|
z
|
≤ 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(2k)! Z ^ {2k + 1}}} {2 ^ {2k} (k!) ^ {2} (2k +1)}}=\arcsin z,|z|\równik 1}
∑
k =
0
∞
( - 1
)
k
( 2 k ) !
z
2 k + 1
2
2 k
( k !
)
2
( 2 k + 1 )
= arcsinh
z
,
|
z
|
≤ 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k} (2k)! Z ^ {2k + 1}} {2 ^ {2k} (k!) ^{2}(2k+1)}}=\operatorname {arcsinh} {z},|z|\leq 1}
∑
k =
0
∞
( - 1
)
k
z
2 k + 1
2 k + 1
= arctan z ,
|
z
|
< 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k} z ^ {2k + 1}} {2k + 1}} = \ arctan z, | z|<1}
∑
k =
0
∞
z
2 k + 1
2 k + 1
= arctanh z ,
|
z
|
< 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {z ^ {2k + 1}} {2k + 1}} = \ operatorname {arctanh} z, | z| <1}
ln 2 +
∑
k = 1
∞
( - 1
)
k - 1
( 2 k ) !
z
2 k
2
2 k + 1
k ( k !
)
2
= ln
(
1 +
1 +
z
2
)
,
|
z
|
≤ 1
{\ Displaystyle \ ln 2+ \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1) ^ {k-1} (2k)! z ^ {2k}}} {2 ^ {2k+ 1}k(k!)^{2}}}=\ln \left(1+{\sqrt {1+z^{2}}}\right),|z|\leq 1}
Zmodyfikowane mianowniki silni
∑
k =
0
∞
( 4 k ) !
2
4 k
2
( 2 k ) ! ( 2 k + 1 ) !
z
k
=
1 -
1 - z
z
,
|
z
|
< 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(4k)!} {2 ^ {4k} {\ sqrt {2}} (2k)! (2k + 1)! }}z^{k}={\sqrt {\frac {1-{\sqrt {1-z}}}{z}}},|z|<1}
∑
k =
0
∞
2
2 k
( k !
)
2
( k + 1 ) ( 2 k + 1 ) !
z
2 k + 2
=
(
arcsin
z
)
2
,
|
z
|
≤ 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {2 ^ {2k} (k!) ^ {2}} {(k + 1) (2k + 1)!}} z^{2k+2}=\left(\arcsin {z}\right)^{2},|z|\leq 1}
∑
n =
0
∞
∏
k =
0
n - 1
( 4
k
2
+
α
2
)
( 2 n ) !
z
2 n
+
∑
n =
0
∞
α
∏
k =
0
n - 1
[ ( 2 k + 1
)
2
+
α
2
]
( 2 n
+ 1 ) !
z
2 n + 1
=
mi
α arcsin
z
,
|
z
|
≤ 1
{\ Displaystyle \ suma _ {n = 0} ^ {\ infty} {\ Frac {\ prod _ {k = 0} ^ {n-1} (4k ^ {2} + \ alfa ^ {2}) }{(2n)!}}z^{2n}+\sum _{n=0}^{\infty }{\frac {\alpha \prod _{k=0}^{n-1}[(2k +1)^{2}+\alpha ^{2}]}{(2n+1)!}}z^{2n+1}=e^{\alpha \arcsin {z}},|z|\leq 1}
Współczynniki dwumianowe
( 1 + z
)
α
=
∑
k =
0
∞
(
α k
)
z
k
,
|
z
|
( patrz
_
_ Twierdzenie dwumianowe § Uogólnione twierdzenie dwumianowe Newtona )
∑
k =
0
∞
(
α + k - 1
k
)
z
k
=
1
( 1 - z
)
α
,
|
z
|
< 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {{\ alfa + k-1} \ wybierz k} z ^ {k} = {\ Frac {1} {(1-z) ^ {\alfa}}},|z|<1}
∑
k =
0
∞
1
k + 1
(
2 k
k
)
z
k
=
1 -
1 - 4 z
2 z
,
|
z
|
≤
1 4
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty}} {\ Frac {1} {k + 1}} {2k \ wybierz k} z ^ {k} = {\ Frac {1- { \sqrt {1-4z}}}{2z}},|z|\leq {\frac {1}{4}}}
, funkcja generująca liczby katalońskie
∑
k =
0
∞
(
2 k
k
)
z
k
=
1
1 - 4 z
,
|
z
|
<
1 4
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {2k \ wybierz k} z ^ {k} = {\ Frac {1} {\ sqrt {1-4z}}}, | z |<{\frac {1}{4}}}
, funkcja generująca współczynniki centralnego dwumianu
∑
k =
0
∞
(
2 k + α
k
)
z
k
=
1
1 - 4 z
(
1 -
1 - 4 z
2 z
)
α
,
|
z
|
<
1 4
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {2k + \ alfa \ wybierz k} z ^ {k} = {\ Frac {1} {\ sqrt {1-4z}}} \ left({\frac {1-{\sqrt {1-4z}}}{2z}}\right)^{\alpha},|z|<{\frac {1}{4}}}
Liczby harmoniczne
(Patrz liczby harmoniczne , same zdefiniowane
H
n
=
∑
jot = 1
n
1 jot
{\ textstyle H_ {n} = \ suma _ {j = 1} ^ {n} {\ Frac {1} {j}}}
)
∑
k = 1
∞
H.
k
z
k
=
- ln ( 1 - z )
1 - z
,
|
z
|
< 1
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} H_ {k} z ^ {k} = {\ Frac {- \ ln (1-z)} {1-z}}, | z |<1}
∑
k = 1
∞
H.
k
k + 1
z
k + 1
=
1 2
[
ln ( 1 - z )
]
2
,
|
z
|
< 1
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {H_ {k}} {k + 1}} z ^ {k + 1} = {\ Frac {1} {2} }\left[\ln(1-z)\right]^{2},\qquad |z|<1}
∑
k = 1
∞
( - 1
)
k - 1
H.
2 k
2 k + 1
z
2 k + 1
=
1 2
arctan
z
log
( 1 +
z
2
)
,
|
z
|
< 1
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1) ^ {k-1} H_ {2k}} {2k + 1}} z ^ {2k + 1} = { \frac {1}{2}}\arctan {z}\log {(1+z^{2})},\qquad |z|<1}
∑
n =
0
∞
∑
k =
0
2 n
( - 1
)
k
2 k + 1
z
4 n + 2
4 n + 2
=
1 4
arctan
z
log
1 + z
1 - z
,
|
z
|
< 1
{\ Displaystyle \ suma _ {n = 0} ^ {\ infty} \ suma _ {k = 0} ^ {2n} {\ Frac {(-1) ^ {k}} {2k + 1}} {\ frac {z^{4n+2}}{4n+2}}={\frac {1}{4}}\arctan {z}\log {\frac {1+z}{1-z}},\qquad |z|<1}
Współczynniki dwumianowe
∑
k =
0
n
(
n k
)
=
2
n
{\ Displaystyle \ suma _ {k = 0} ^ {n} {n \ wybierz k} = 2 ^ {n}}
0
∑
k =
0
n
( - 1
)
k
(
n k
)
= ,
gdzie
n ≥ 1
{\ Displaystyle \ suma _ {k = 0} ^ {n} (-1) ^ {k} {n \ wybierz k} = 0 ,{\text{ gdzie }}n\geq 1}
∑
k =
0
n
(
k m
)
=
(
n + 1
m + 1
)
{\ Displaystyle \ suma _ {k = 0} ^ {n} {k \ wybierz m} = {n + 1 \ wybierz m + 1}}
∑
k =
0
n
(
m + k - 1
k
)
=
(
n + m
n
)
{\ Displaystyle \ suma _ {k = 0} ^ {n} {m + k-1 \ wybierz k} = {n + m \ wybierz n}}
(patrz Multiset )
∑
k =
0
n
(
α k
)
(
β
n - k
)
=
(
α + β
n
)
{\ Displaystyle \ suma _ {k = 0} ^ {n} {\ alfa \ wybierz k} {\ beta \ wybierz nk} ={\alpha +\beta \choose n}}
(zobacz tożsamość Vandermonde'a )
Funkcje trygonometryczne
Sumy sinusów i cosinusów powstają w szeregach Fouriera .
0
∑
k = 1
∞
sałata ( k θ )
k
= -
1 2
ln ( 2 - 2 sałata θ ) = - ln
(
2 grzech
θ 2
)
, < θ < 2 π
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {\ cos (k \ theta)}} {k}} = - {\ Frac {1} {2}} \ ln (2-2 \cos \theta )=-\ln \left(2\sin {\frac {\theta }{2}}\right),0<\theta <2\pi}
0
∑
k = 1
∞
grzech ( k θ )
k
=
π - θ
2
, < θ < 2 π
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {\ sin (k \ theta) }{k}}={\frac {\pi -\theta}{2}},0<\theta<2\pi}
0
∑
k = 1
∞
( - 1
)
k - 1
k
sałata ( k θ ) =
1 2
ln ( 2 + 2 sałata θ ) = ln
(
2 sałata
θ 2
)
, ≤ θ < π
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1) ^ {k-1}} {k}} \ cos (k \ theta) = {\ frac {1} 2}}\ln(2+2\cos \theta )=\ln \left(2\cos {\frac {\theta }{2}}\right),0\leq \theta <\pi }
∑
k = 1
∞
( - 1
)
k - 1
k
grzech ( k θ ) =
θ 2
, -
π 2
≤ θ ≤
π 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ frac {(-1)^{k-1}}{k}}\sin(k\theta )={\frac {\theta}{2}},-{\frac {\pi}}{2}}\leq \theta \leq {\frac {\pi }{2}}}
0
∑
k = 1
∞
sałata ( 2 k θ )
2 k
= -
1 2
ln ( 2 grzech θ ) , < θ < π
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ frac {\cos(2k\theta )}{2k}}=-{\frac {1}{2}}\ln(2\sin \theta ),0<\theta <\pi}
0
∑
k = 1
∞
grzech ( 2 k θ )
2 k
=
π - 2 θ
4
, < θ < π
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {\ sin (2k \ theta )}{2k}}={\frac {\pi -2\theta}{4}},0<\theta <\pi}
0
∑
k =
0
∞
sałata [ ( 2 k + 1 ) θ ]
2 k + 1
=
1 2
ln
(
łóżeczko
θ 2
)
, < θ < π
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty }{\frac {\cos[(2k+1)\theta]}{2k+1}}={\frac {1}{2}}\ln \left(\cot {\frac {\theta}{2 }}\right),0<\theta <\pi }
0
∑
k =
0
∞
grzech [ ( 2 k + 1 ) θ ]
2 k + 1
=
π 4
, < θ < π
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {\ sin [ (2k+1)\theta ]}{2k+1}}={\frac {\pi }{4}},0<\theta <\pi}
,
∑
k = 1
∞
grzech ( 2 π k x )
k
= π
(
1 2
- { x }
)
, x ∈
R
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {\ sin (2\pi kx)}{k}}=\pi \left({\dfrac {1}{2}}-\{x\}\right),\ x\in \mathbb {R}}
∑
k = 1
∞
grzech
(
2 π k x
)
k
2 n - 1
= ( - 1
)
n
( 2 π
)
2 n - 1
2 ( 2 n - 1 ) !
b
2 n - 1
( { x } ) , x ∈
R
, n ∈
N
{\ Displaystyle \ suma \ ograniczenia _ {k = 1} ^ {\ infty}} {\ Frac {\ sin \ lewo (2 \ pi kx \ prawej)} {k ^ {2n-1}}} =(-1)^{n}{\frac {(2\pi )^{2n-1}}{2(2n-1)!}}B_{2n-1}(\{x\}),\ x\in \mathbb {R} ,\ n\in \mathbb {N}}
∑
k = 1
∞
sałata
(
2 π k x
)
k
2 n
= ( - 1
)
n - 1
( 2 π
)
2 n
2 ( 2 n ) !
b
2 n
( { x } ) , x ∈
R
, n ∈
N
{\ Displaystyle \ suma \ limity _ {k = 1} ^ {\ infty}} {\ Frac {\ cos \ lewo (2 \ pi kx \ prawo)}} {k ^ {2n}}} = (-1) ^ { n-1}{\frac {(2\pi )^{2n}}{2(2n)!}}B_{2n}(\{x\}),\ x\in \mathbb {R} ,\ n \in \mathbb {N} }
0
b
n
( x ) = -
n !
2
n - 1
π
n
∑
k = 1
∞
1
k
n
sałata
(
2 π k x -
π n
2
)
, < x < 1
{\ Displaystyle B_ {n} (x) = - {\ Frac {n!} {2^{n-1}\pi ^{n}}}\sum _{k=1}^{\infty}{\frac {1}{k^{n}}}\cos \left(2\ pi kx-{\frac {\pi n}{2}}\right),0<x<1}
∑
k =
0
n
grzech ( θ + k α ) =
grzech
( n + 1 ) α
2
grzech ( θ +
n α
2
)
grzech
α 2
{\ Displaystyle \ suma _ {k = 0} ^ {n} \sin(\theta +k\alpha)={\frac {\sin {\frac {(n+1)\alpha}{2}}\sin(\theta +{\frac {n\alpha}}{2} })} {\ sin {\ frac {\ alfa} {2}}}}}
∑
k =
0
n
sałata ( θ + k α ) =
grzech
( n + 1 ) α
2
sałata ( θ +
n α
2
)
grzech
α 2
{\ Displaystyle \ suma _ {k = 0} ^ {n} \cos(\theta +k\alpha)={\frac {\sin {\frac {(n+1)\alpha}}{2}}\cos(\theta +{\frac {n\alpha}{2} })} {\ sin {\ frac {\ alfa} {2}}}}}
∑
k = 1
n - 1
grzech
π k
n
= łóżeczko
π
2 n
{\ Displaystyle \ suma _ {k = 1} ^ {n-1} \ sin {\ Frac {\ pi k} {n}} = \ łóżeczko {\ frac {\ pi }{2n}}}
∑
k = 1
n - 1
grzech
2 π k
n
=
0
{\ Displaystyle \ suma _ {k = 1} ^ {n-1} \ sin {\ Frac {2 \ pi k} {n}} = 0}
∑
k =
0
n - 1
csc
2
(
θ +
π k
n
)
=
n
2
csc
2
( n θ )
{\ Displaystyle \ suma _ {k = 0} ^ {n-1} \ csc ^ {2} \ left(\theta +{\frac {\pi k}{n}}\right)=n^{2}\csc ^{2}(n\theta)}
∑
k = 1
n - 1
csc
2
π k
n
=
n
2
- 1
3
{\ Displaystyle \ suma _ {k = 1} ^ {n-1} \ csc ^ {2} {\ Frac {\ pi k} {n}}={\frac {n^{2}-1}{3}}}
∑
k = 1
n - 1
csc
4
π k
n
=
n
4
+ 10
n
2
- 11
45
{\ Displaystyle \ suma _ {k = 1} ^ {n-1} \ csc ^ {4} {\ Frac { \pi k}{n}}={\frac {n^{4}+10n^{2}-11}{45}}}
Funkcje wymierne
∑
n = za + 1
∞
za
n
2
-
za
2
=
1 2
H.
2 za
{\ Displaystyle \ suma _ {n = a + 1} ^ {\ infty} {\ Frac {a} {n ^ {2} - a^{2}}}={\frac {1}{2}}H_{2a}}
∑
n =
0
∞
1
n
2
+
za
2
=
1 + za π coth ( za π )
2
za
2
{\ Displaystyle \ suma _ {n = 0} ^ {\ infty} {\ Frac {1} {n ^ { 2}+a^{2}}}={\frac {1+a\pi \coth(a\pi )}{2a^{2}}}}
∑
n =
0
∞
1
n
4
+ 4
za
4
=
1
8
za
4
+
π ( sinh ( 2 π za ) + grzech ( 2 π za ) )
8
za
3
( pałka ( 2 π za ) - sałata ( 2 π za
) )
{\ Displaystyle \ Displaystyle \ suma _ {n = 0} ^ {\ infty} {\ Frac {1} {n ^ {4} + 4a ^ {4}}} = {\ dfrac {1} {8a ^ {4}}}+{\dfrac {\pi (\sinh(2\pi a)+\sin(2\pi a))}{8a^{3}(\cosh(2\pi a)-\cos (2\pi a))}}}
Nieskończony szereg dowolnej funkcji wymiernej
można
wyjaśniono
zredukować do skończonego szeregu funkcji poligammy , stosując częściowy rozkład ułamków , jak tutaj . Fakt ten można również zastosować do skończonych szeregów funkcji wymiernych, umożliwiając obliczenie wyniku w stałym czasie , nawet jeśli szereg zawiera dużą liczbę wyrazów.
Funkcja wykładnicza
1
p
∑
n =
0
p - 1
exp
(
2 π ja
n
2
q
p
)
=
mi
π ja
/
4
2 q
∑
n =
0
2 q - 1
exp
(
-
π ja
n
2
p
2 q
)
{\ Displaystyle \ Displaystyle {\ dfrac {1} {\ sqrt {p}}} \ suma _ {n = 0} ^ {p-1} \ exp \ lewo ({\ Frac {2 \ pi w ^ {2} q}{p}}\right)={\dfrac {e^{\pi i/4}}{\sqrt {2q}}}\sum _{n=0}^{2q-1}\exp \left (-{\frac {\pi in^{2}p}{2q}}\right)}
(patrz relacja Landsberga-Schaara )
∑
n = - ∞
∞
mi
- π
n
2
=
π
4
Γ
(
3 4
)
{\ Displaystyle \ Displaystyle \ suma _ {n = - \ infty} ^ {\ infty} e ^ {- \ pi n ^ {2} }={\frac {\sqrt[{4}]{\pi}}{\Gamma \left({\frac {3}{4}}\right)}}}
Serie liczbowe
Te serie liczbowe można znaleźć, podłączając liczby z serii wymienionych powyżej.
Naprzemienne szeregi harmoniczne
∑
k = 1
∞
( - 1
)
k + 1
k
=
1 1
-
1 2
+
1 3
-
1 4
+ ⋯ = ln 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1)^{k+1}}{k}}={\frac {1}{1}}-{\frac {1}{2}}+{\frac {1}{3}}- {\frac {1}{4}}+\cdots =\ln 2}
∑
k = 1
∞
( - 1
)
k + 1
2 k - 1
=
1 1
-
1 3
+
1 5
-
1 7
+
1 9
- ⋯ =
π 4
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty }{\frac {(-1)^{k+1}}{2k-1}}={\frac {1}{1}}-{\frac {1}{3}}+{\frac { 1}{5}}-{\frac {1}{7}}+{\frac {1}{9}}-\cdots ={\frac {\pi}}}}
Suma odwrotności silni
∑
k =
0
∞
1
k !
=
1
0
!
+
1
1 !
+
1
2 !
+
1
3 !
+
1
4 !
+ ⋯ = mi
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {1} {k!}} = {\ Frac {1} {0!}} + {\ Frac {1} {1!}}+{\frac {1}{2!}}+{\frac {1}{3!}}+{\frac {1}{4!}}+\cdots =e}
∑
k =
0
∞
1
( 2 k ) !
=
1
0
!
+
1
2 !
+
1
4 !
+
1
6 !
+
1
8 !
+ ⋯ =
1 2
(
mi +
1 mi
)
= paczka 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {1} {(2k)!}} = {\ Frac {1} {0!}} + {\ Frac {1} {2} !}}+{\frac {1}{4!}}+{\frac {1}{6!}}+{\frac {1}{8!}}+\cdots ={\frac {1}{ 2}}\left(e+{\frac {1}{e}}\right)=\cosh 1}
∑
k =
0
∞
1
( 3 k ) !
=
1
0
!
+
1
3 !
+
1
6 !
+
1
9 !
+
1
12 !
+ ⋯ =
1 3
(
mi +
2
mi
sałata
3
2
)
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {1} {(3k)!}} = {\ Frac {1} {0!}} + {\ Frac {1} {3} !}}+{\frac {1}{6!}}+{\frac {1}{9!}}+{\frac {1}{12!}}+\cdots ={\frac {1}{ 3}}\left(e+{\frac {2}{\sqrt {e}}}\cos {\frac {\sqrt {3}}{2}}\right)}
∑
k =
0
∞
1
( 4 k ) !
=
1
0
!
+
1
4 !
+
1
8 !
+
1
12 !
+
1
16 !
+ ⋯ =
1 2
(
sałata 1 + paczka 1
)
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {1} {(4k)!}} = {\ Frac {1} {0!}} + {\ Frac {1} {4} !}}+{\frac {1}{8!}}+{\frac {1}{12!}}+{\frac {1}{16!}}+\cdots ={\frac {1}{ 2}}\lewo(\cos 1+\cosh 1\prawo)}
Trygonometria i π
∑
k =
0
∞
( - 1
)
k
( 2 k + 1 ) !
=
1
1 !
−
1
3 !
+
1
5 !
−
1
7 !
+
1
9 !
+ ⋯ = grzech 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k}} {(2k + 1)!}} = {\ Frac {1} {1!}} -{\frac {1}{3!}}+{\frac {1}{5!}}-{\frac {1}{7!}}+{\frac {1}{9!}}+\ cdots =\sin 1}
∑
k =
0
∞
( - 1
)
k
( 2 k ) !
=
1
0
!
−
1
2 !
+
1
4 !
−
1
6 !
+
1
8 !
+ ⋯ = sałata 1
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {(-1) ^ {k}} {(2k)!}} = {\ Frac {1} 0!}}-{\frac {1}{2!}}+{\frac {1}{4!}}-{\frac {1}{6!}}+{\frac {1}{8! }}+\cdots =\cos 1}
∑
k = 1
∞
1
k
2
+ 1
=
1 2
+
1 5
+
1 10
+
1 17
+ ⋯ =
1 2
( π coth π - 1 )
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty }{\frac {1}{k^{2}+1}}={\frac {1}{2}}+{\frac {1}{5}}+{\frac {1}{10}} +{\frac {1}{17}}+\cdots ={\frac {1}{2}}(\pi \coth \pi -1)}
∑
k = 1
∞
( - 1
)
k
k
2
+ 1
= -
1 2
+
1 5
-
1 10
+
1 17
+ ⋯ =
1 2
( π csch π - 1 )
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1) ^ {k}} {k ^ {2} + 1}} = - {\ Frac {1} {2} }+{\frac {1}{5}}-{\frac {1}{10}}+{\frac {1}{17}}+\cdots ={\frac {1}{2}}(\ pi \nazwa_operatora {csch} \pi -1)}
3 +
4
2 × 3 × 4
-
4
4 × 5 × 6
+
4
6 × 7 × 8
-
4
8 × 9 × 10
+ ⋯ = π
{\ Displaystyle 3 + {\ Frac {4} {2 \ razy 3 \ razy 4}}-{\frac {4}{4\razy 5\razy 6}}+{\frac {4}{6\razy 7\razy 8}}-{\frac {4}{8\razy 9 \times 10}}+\cdots =\pi }
Odwrotność liczb trójkątnych
∑
k = 1
∞
1
T
k
=
1 1
+
1 3
+
1 6
+
1 10
+
1 15
+ ⋯ = 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {1} T_{k}}}={\frac {1}{1}}+{\frac {1}{3}}+{\frac {1}{6}}+{\frac {1}{10}} +{\frac {1}{15}}+\cdots =2}
gdzie
T
n
=
∑
k = 1
n
k
{\ Displaystyle T_ {n} = \ suma _ {k = 1} ^ {n} k}
Odwrotność liczb czworościennych
∑
k = 1
∞
1
T
mi
k
=
1 1
+
1 4
+
1 10
+
1 20
+
1 35
+ ⋯ =
3 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {1 }{Te_{k}}}={\frac {1}{1}}+{\frac {1}{4}}+{\frac {1}{10}}+{\frac {1}{20 }}+{\frac {1}{35}}+\cdots ={\frac {3}{2}}}
gdzie
T
mi
n
=
∑
k = 1
n
T
k
{\ Displaystyle Te_ {n} = \ suma _ {k = 1} ^ {n} T_ {k}}
Wykładniczy i logarytm
∑
k =
0
∞
1
( 2 k + 1 ) ( 2 k + 2 )
=
1
1 × 2
+
1
3 × 4
+
1
5 × 6
+
1
7 × 8
+
1
9 × 10
+ ⋯ = ln 2
{\ Displaystyle \ suma _ {k = 0} ^ {\ infty} {\ Frac {1} {(2k + 1) (2k + 2)}} = {\ Frac {1} {1 \ razy 2}} + {\frac {1}{3\times 4}}+{\frac {1}{5\times 6}}+{\frac {1}{7\times 8}}+{\frac {1}{9 \times 10}}+\cdots =\ln 2}
∑
k = 1
∞
1
2
k
k
=
1 2
+
1 8
+
1 24
+
1 64
+
1 160
+ ⋯ = ln 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {\ Frac { 1}{2^{k}k}}={\frac {1}{2}}+{\frac {1}{8}}+{\frac {1}{24}}+{\frac {1 }{64}}+{\frac {1}{160}}+\cdots =\ln 2}
∑
k = 1
∞
( - 1
)
k + 1
2
k
k
+
∑
k = 1
∞
( - 1
)
k + 1
3
k
k
=
(
1 2
+
1 3
)
-
(
1 8
+
1 18
)
+
(
1 24
+
1
81
)
-
(
1 64
+
1 324
)
+ ⋯ = ln 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {(-1) ^ {k + 1}} {2 ^ {k}k}}+\sum _{k=1}^{\infty}{\frac {(-1)^{k+1}}{3^{k}k}}={\Bigg (} {\frac {1}{2}}+{\frac {1}{3}}{\Bigg )}-{\Bigg (}{\frac {1}{8}}+{\frac {1}{ 18}}{\Bigg )}+{\Bigg (}{\frac {1}{24}}+{\frac {1}{81}}{\Bigg )}-{\Bigg (}{\frac { 1}{64}}+{\frac {1}{324}}{\Bigg )}+\cdots =\ln 2}
∑
k = 1
∞
1
3
k
k
+
∑
k = 1
∞
1
4
k
k
=
(
1 3
+
1 4
)
+
(
1 18
+
1 32
)
+
(
1 81
+
1 192
)
+
(
1 324
+
1 1024
)
+ ⋯
= ln 2
{\ Displaystyle \ suma _ {k = 1} ^ {\ infty} {\ Frac {1} {3 ^ {k} k}} + \ suma _ {k = 1} ^ {\ infty}} \frac {1}{4^{k}k}}={\Bigg (}{\frac {1}{3}}+{\frac {1}{4}}{\Bigg )}+{\Bigg (}{\frac {1}{18}}+{\frac {1}{32}}{\Bigg )}+{\Bigg (}{\frac {1}{81}}+{\frac {1 }{192}}{\Bigg )}+{\Bigg (}{\frac {1}{324}}+{\frac {1}{1024}}{\Bigg )}+\cdots =\ln 2}
Zobacz też
Notatki