Riemann Zeta Function of 4/Proof 4

From ProofWiki
Jump to navigation Jump to search

Theorem

The Riemann zeta function of $4$ is given by:

\(\ds \map \zeta 4\) \(=\) \(\ds \dfrac 1 {1^4} + \dfrac 1 {2^4} + \dfrac 1 {3^4} + \dfrac 1 {4^4} + \cdots\)
\(\ds \) \(=\) \(\ds \dfrac {\pi^4} {90}\)
\(\ds \) \(\approx\) \(\ds 1 \cdotp 08232 \, 3 \ldots\)


Proof

\(\ds \map \zeta 4\) \(=\) \(\ds \paren {-1}^3 \dfrac {B_4 2^3 \pi^4} {4!}\) Riemann Zeta Function at Even Integers
\(\ds \) \(=\) \(\ds \paren {-1}^3 \paren {-\dfrac 1 {30} } \dfrac {2^3 \pi^4} {4!}\) Definition of Sequence of Bernoulli Numbers
\(\ds \) \(=\) \(\ds \paren {\dfrac 1 {30} } \paren {\dfrac 8 {24} } \pi^4\) Definition of Factorial
\(\ds \) \(=\) \(\ds \dfrac {\pi^4} {90}\) simplifying

$\blacksquare$