Editing Trigonometric integral (section)

== Hyperbolic cosine integral ==
The [[hyperbolic cosine]] integral is
[[File:Plot of the hyperbolic cosine integral function Chi(z) in the complex plane from -2-2i to 2+2i with colors created with Mathematica 13.1 function ComplexPlot3D.svg|alt=Plot of the hyperbolic cosine integral function Chi(''z'') in the complex plane from −2&nbsp;−&nbsp;2''i'' to 2&nbsp;+&nbsp;2''i''|thumb|Plot of the hyperbolic cosine integral function {{math|Chi(''z'')}} in the complex plane from {{math|−2 − 2''i''}} to {{math|2 + 2''i''}}]]
<math display="block">\operatorname{Chi}(x) = \gamma+\ln x + \int_0^x\frac{\cosh t-1}{t}\,dt \qquad ~ \text{ for } ~ \left| \operatorname{Arg}(x) \right| < \pi~,</math>
where <math>\gamma</math> is the [[Euler–Mascheroni constant]].

It has the series expansion
<math display="block">\operatorname{Chi}(x) = \gamma + \ln(x) + \frac {x^2}{4} + \frac {x^4}{96} + \frac {x^6}{4320} + \frac {x^8}{322560} + \frac{x^{10}}{36288000} + O(x^{12}).</math>