Log Function |
No
Log(number)
number
Use: Required
Data Type: Double
A numeric expression greater than zero.
A Double.
Returns the natural logarithm of a given number.
The natural logarithm is based on e, a constant whose value is approximately 2.718282. The natural logarithm is expressed by the equation:
ez = x
where z = Log(x). In other words, the natural logarithm is the inverse of the exponential function.
number, the value whose natural logarithm the function is to return, must be a positive real number. If number is negative or zero, the function generates runtime error 5, "Invalid procedure call or argument."
You can calculate base-n logarithms for any number, x, by dividing the natural logarithm of x by the natural logarithm of n, as the following expression illustrates:
Logn(x) = Log(x) / Log(n)
For example, the Log10 function shows the source code for a custom function that calculates base-10 logarithms:
Static Function Log10(X) Log10 = Log(X) / Log(10#) End Function
A number of other mathematical functions that aren't intrinsic to VBA can be computed using the value returned by the Log function. The functions and their formulas are:
Inverse Hyperbolic Sine
HArcsin(X) = Log(X + Sqr(X * X + 1))
Inverse Hyperbolic Cosine
HArccos(X) = Log(X + Sqr(X * X - 1))
Inverse Hyperbolic Tangent
HArctan(X) = Log((1 + X) / (1 - X)) / 2
Inverse Hyperbolic Secant
HArcsec(X) = Log((Sqr(-X * X + 1) + 1) / X)
Inverse Hyperbolic Cosecant
HArccosec(X) = Log((Sgn(X) * Sqr(X * X + 1) +1) / X)
Inverse Hyperbolic Cotangent