Difference between revisions of "Relationship between cosine and hypergeometric 0F1"

Theorem: The following formula holds: $$\cos(z)={}_0F_1 \left(;\dfrac{1}{2};-\dfrac{z^2}{4} \right),$$ where $\cos$ denotes the cosine and ${}_0F_1$ denotes the hypergeometric pFq.