**Public Function CosH( _
ByVal vX As Variant _
) As Variant**

**"Hyperbolic Cosine" **

Hyperbolic cosine of a real or complex number.

Inverse of the ACosH function.

**Examples:** CosH(-1) = 1.54308063481524
CosH(-0.5) = 1.12762596520638
CosH(0) = 1
CosH(0.5) = 1.12762596520638
CosH(1) = 1.54308063481524
CosH(10) = 11013.2329201033
CosH("2.3|-4.5") = "-1.06182495367184|4.82602885468343"

**See also:** Cosine Function
SinH Function
TanH Function
CscH Function
ACosH Function
HCos Function

**vX:** Number whose hyperbolic cosine is returned. Function returns Null if vX is Null or cannot be fixed up to a real or complex number (as defined by the ComplexStringToReals function). Complex numbers are represented within strings as "R|I" where R is the real part and I is the imaginary part.

**Return:** The result is expressed in radians.

**Note:** Microsoft named this function HCos within their Derived Math Function help topic. **Definition:**

(Exponent(X) + Exponent(-X)) / 2

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