## A Cos H FunctionMath Trig Complex Class

```Public Function ACosH( _
ByVal vX As Variant _
) As Variant```

### "Inverse Hyperbolic Cosine" Angle whose hyperbolic cosine is X. Inverse of the CosH function.

Examples:
```    ACosH(-10) = 2.99322284612638
ACosH(-2) = 1.31695789692482
ACosH(-1) = 0
ACosH(0) = "0|1.5707963267949"
ACosH(-0.5) = "3.33066907387547E-16|1.0471975511966"
ACosH(1) = 0
ACosH(2) = 1.31695789692482
ACosH(10) = 2.99322284612638
ACosH("2.3|-4.5") = "2.1552640881525|-0.560507402681906"```
```    ACos Function
CosH Function
ASinH Function
ATanH Function
ACscH Function
HArccos Function```
vX: Function returns the principal value of the angle whose hyperbolic cosine (expressed in radians) is vX. 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.
Note: Microsoft named this function HArccos within their Derived Math Function help topic.

Definition:

`    Logarithm(Absolute(X) + Sqrt((X - 1) * (X + 1)))`