Evaluate ∑n=0∞(−1)nn!⋅4n\sum_{n=0}^{\infty} \frac{(-1)^n}{n! \cdot 4^n}∑n=0∞n!⋅4n(−1)n as a function value.
e1/4e^{1/4}e1/4
e−1/4e^{-1/4}e−1/4
e−4e^{-4}e−4
cos(1/4)\cos(1/4)cos(1/4)