find the logarithm of a number in ruby

To find the logarithm of a number in Ruby, you can use the Math module's logarithmic functions. The most commonly used logarithmic functions are log, log10, and log2.

The log function can take one or two arguments. If only one argument is provided, it returns the natural logarithm (base e) of that number. If two arguments are provided, then the second argument is the base.

Here's an example of using log to find the log base 10 of a number:

main.rb
num = 100
log10_num = Math.log10(num)

puts log10_num # output: 2.0
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Alternatively, you can use the log2 function to find the log base 2 of a number:

main.rb
num = 8
log2_num = Math.log2(num)

puts log2_num # output: 3.0
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If you need to find the logarithm of a number with a base other than e, you can use the change of base formula:

log_a (b) = log_c (b) / log_c (a)

Here's an example of finding the log base 3 of a number using the change of base formula:

main.rb
num = 81
base = 3

log_num_base = Math.log(num) / Math.log(base)

puts log_num_base # output: 4.0
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