E(2,1)(z)=cosh(sqrt(z))
From specialfunctionswiki
Theorem
The following formula holds for $z \in \mathbb{C}$: $$E_{2,1}(z)=\cosh(\sqrt{z}),$$ where $E_{2,1}$ denotes the Mittag-Leffler function and $\cosh$ denotes cosh.
Proof
References
- H.J. Haubold, A.M. Mathai and R.K. Saxena: Mittag-Leffler Functions and Their Applications (2011)... (previous)... (next): $(2.3)$ (uses notation $E_2$ instead of $E_{2,1}$)
