Cosine
From specialfunctionswiki
The cosine function, $\cos \colon \mathbb{C} \rightarrow \mathbb{C}$ is defined by the formula $$\cos(z)=\dfrac{e^{iz}+e^{-iz}}{2},$$ where $e^z$ is the exponential function.
Graph of $\cos$ on $[-2\pi,2\pi]$.
Domain coloring of $\cos$.
Properties
Derivative of cosine
Taylor series of cosine
Weierstrass factorization of cosine
Beta in terms of sine and cosine
Relationship between cosine and hypergeometric 0F1
Relationship between spherical Bessel y sub nu and cosine
Relationship between cosh and cos
Relationship between cos and cosh
Relationship between cosine, Gudermannian, and sech
Relationship between sech, inverse Gudermannian, and cos
