Definition:Cosine Integral Function

Definition
The cosine integral function is the real function defined as:


 * $\operatorname{Ci}: \left({0 \,.\,.\, \to}\right] \to \R$:


 * $\operatorname{Ci} \left({x}\right) = -\displaystyle \int_{t \mathop = x}^{t \mathop \to +\infty} \frac {\cos t} t \, \mathrm d t$

Graph

 * CiFunction.png

Also see

 * Characterization of Cosine Integral Function