find the logarithm of a number in swift

To find the logarithm of a number in Swift, you can use the built-in log() function provided by the Foundation framework.

main.swift
import Foundation

let x = 10.0
let result = log(x) // natural logarithm of 10
print(result) // 2.302585092994046
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The log() function takes a single argument that represents the number whose logarithm is to be calculated. By default, the function calculates the natural logarithm (base e) of the input number.

If you want to calculate the logarithm of a number with a different base, you can use the change of base formula. For example, to calculate the logarithm of x with base b, you can use the following formula:

main.swift
log_b(x) = log_e(x) / log_e(b)
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Here's an example of how to use the change of base formula in Swift:

main.swift
let x = 100.0
let base = 10.0
let result = log(x) / log(base) // logarithm of 100 with base 10
print(result) // 2.0
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In this example, we first calculate the natural logarithm of x using the log() function. We then divide this result by the natural logarithm of the desired base (10) to obtain the logarithm of x with base 10.