f(x)= 1/(1+2^lgx) + ...;f(1/x)= 1/(1+2^lg(1/x)) + ...= 1/(1+2^(-lgx))+ ...f(x)+f(1/x) = 1/(1+2^lgx) + 1/(1+2^(-lgx)) + ...= {1+2^lgx+1+2^(-lgx)}/{1+2^lgx+2^(-lgx)+2^lgx*2^(-lgx)+ ...= (1+ 1 2^(lgx-lgx...