# Derive base 10 logarithm from base 2 log output

2 views (last 30 days)
Jogger on 15 Nov 2021
Commented: Jogger on 15 Nov 2021
Hi
I am looking to calculate .
• log10 with base2log as input.i.e. log10(log2())
• log() with base2log as input i.e. log(log2())
I have only base2log function available for calculation and I don't have common log() and log10() available
Below is my code and I am looking for the right mathematical formula for conversion so that I can get equivalent log() and log10() using log2()
Thank you!!
input = 32;
b = log2(input);
constant = 2.30258509299405; % assuming log(10)
base10 = log(b) / (constant) % formula for conversion, I don't have log function available
base10 = 0.6990
output = log10(b)
output = 0.6990
nlog = log(input) % need conversion formula
nlog = 3.4657
nlog = log(32)/log(2.718281828)
nlog = 3.4657

Chunru on 15 Nov 2021
The formula is:
For any given base b, you need to compute a constant .
Jogger on 15 Nov 2021
Thank you !! Works well

R2021b

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