Working with Exponents and Logarithms

Problem

You need to do some calculations that involve exponents and logarithms.

Solution

Use Javascript’s Math object to provide common mathematical functions.

# Math.pow(x, y) returns x^y
Math.pow(2, 4)
# => 16

# Math.exp(x) returns E^x and is shorthand for Math.pow(Math.E, x)
Math.exp(2)
# => 7.38905609893065

# Math.log returns the natural (base E) log
Math.log(5)
# => 1.6094379124341003
Math.log(Math.exp(42))
# => 42

# To get a log with some other base n, divide by Math.log(n)
Math.log(100) / Math.log(10)
# => 2

Discussion

For more information on the Math object see the documentation on the Mozilla Developer Network. Also refer to Math Constants for discussion of the various constants in the Math object.