>>F(x/y) = log(x/y)
>>F(x) = log(x)
>>F(y) = -log(y)
>>
>>e.g.
>>log(x/y) = log(x)+(-log(y)) = log(x)-log(y)
>>
>>x=100
>>y=10
>>
>>(for each y=x*10)
>>
>>log(x/y)=log(10)=1
>>log(10000) = 4
>>
>>works perfect.
>
>If f(x) = log x, then f(y) would be log(y). It must be the same function for both cases, otherwise they would use different letters. Only the argument should be replaced, e.g., if f(x) = log x, then f(10) = log 10, f(10000) = log 10000, and f(y) = log y.

if you use that logic, yes.