# CHI Hyperbolic Cosine Integral

## CHI.1 Introduction |
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Let be a complex variable of .The function Hyperbolic Cosine Integral (noted ) is defined by the following third order differential equation

CHI.1.1 |

The initial conditions of CHI.1.1 at are not simple to state, since is a (regular) singular point.

Related function: Hyperbolic Sine Integral

## CHI.2 Series and asymptotic expansions |
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## CHI.2.1 Asymptotic expansion at |
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## CHI.2.1.1 First terms |
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CHI.2.1.1.1 |

## CHI.2.1.2 General form |
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## CHI.2.2 Asymptotic expansion at |
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## CHI.2.2.2 General form |
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