log a (a/b) + log b (b/a)
= log a a - log a b + log b b - log b a
= 1 - log a b + 1 - log b a
= 2 – ( log a b + log b a )
= 2 – ( logb / loga + loga / logb )
= 2 – (x+1/x) [ loga / logb = x]
Minimum possible value of (x+1/x) is 2 , given x is + ve and real.
Hence Maximum possible value of 2 – (x+1/x) = 0 and cannot be equal to 1