2.8 Functions

2.8 Functions

The mathematical functions give access to the common operations for analysing data and evaluating formulae. The EXP, LN and SQRT functions take the form:

fn(input)

input any valid timeseries input (see section 2.2)

The LOG and POWER functions require a second input and the syntax is:

fn(input, b)

input any valid timeseries input (see section 2.2)

b any valid timeseries input (see section 2.2)

2.8.1 EXP: Exponential, e^x

The term “exp(x)” is the same as writing e^x or ℯ^x or “e to the x” or “ℯ to the power of x”. In this context, “ℯ” is a universal constant, ℯ = 2.718281828…

calc/EXP(input)

Example

calc/EXP(10) = 22,026.465...

2.8.2 LN: Natural Log, ln()

The Natural Log is the inverse of the Exponential function. I.e. ln(ℯ^x) = x. The syntax for the LN function is:

calc/LN(input)

Example

calc/LN(5) = 1.609...

calc/LN(EXP(10)) = 10

Important notes

The following should be noted:

• The ln of a negative number is undefined and will throw a “Not a Number” (NaN) error:

• ln(0) is undefined and will throw a “Not a Number” (NaN) error:

• ln(∞)= ∞

• ln(1)=0

• ln(e)=1

• ln(e^x) = x

• e^ln(x)=x

2.8.3 SQRT: Square Root, √x

Square root of a number is a value, which on multiplication by itself, gives the original number. The square root is an inverse method of squaring a number i.e. x². The syntax for the SQRT function is:

calc/SQRT(input)

Example

calc/SQRT(16) = 4

Tip

The square root function is equivalent to raising a number to the power of ½:

SQRT(x) ≡ POW(x,0.5)

2.8.4 LOG: Logarithm Log_y(x)

The Logarithm is the exponent or power to which a base (b) must be raised to return a given number (x).

Log_b(x)

The syntax for the LOG function is:

calc/LOG(input, b)

input the number for which to find the LOG - any valid timeseries input (see section 2.2)

b the base in which to calculate — any constant or valid timeseries (see section 2.2)

Example

calc/LOG(100,10) = 2

calc/LOG(8,2) = 3

2.8.5 POW: Power, x^y

The POWER function multiplies a number (x) by itself a specified number of times (b). This is often called raising x to the power of b. It is the inverse of the LOG function

x^b

The syntax for the POW function is:

calc/POW(input, b)

input the number to multiply (x) - any valid timeseries input (see section 2.2)

b the power, the number of times to multiply the input by itself— any constant or valid timeseries (see section 2.2)

Example

calc/POW(10,2) = 100

calc/POW(10,-2) = 0.01

calc/POW(2,3) = 8

calc/POW(25,0.5) = 5