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

**"Hyperbolic Secant" **

Hyperbolic secant of a real or complex number.

Inverse of the ASecH function.

**Examples:** SecH(-2) = 0.26580222883408
SecH(-1) = 0.648054273663885
SecH(0) = 1
SecH(1) = 0.648054273663885
SecH(2) = 0.26580222883408
SecH(10) = 9.07998593378172E-05
SecH("2.3|-4.5") = "-4.34852891695235E-02|-0.197642049718895"

**See also:** Secant Function
SinH Function
CotH Function
CscH Function
ASecH Function
HSec Function

**vX:** Number whose hyperbolic secant 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 HSec within their Derived Math Function help topic. **Definition:**

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

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