It's still correct in the sense that you shouldn't repeat the code for calculating the logarithm in every single scenario where you need one. Of course if you need a function for a different purpose then it makes sense to make another one.
Of course mathematics is always an endless game of expanding and contracting definitions so might need some additional versions anyway (most commonly something like f(x) = log(1+x)), though if you're clever about it you can rephrase most of what you want with existing functions.
Of course mathematics is always an endless game of expanding and contracting definitions so might need some additional versions anyway (most commonly something like f(x) = log(1+x)), though if you're clever about it you can rephrase most of what you want with existing functions.