f(x)=x*[1/(2^x-1)+1/2]
=x*[(2+2^x-1)/[2(2^x-1)]]
=x*[(2^x+1)/(2^x-1)]/2
f(-x)=(-x)*[(2^(-x)+1)/(2^(-x)-1)]/2
=(-x)*[(1+2^x)/(1-2^x)]/2
=x*[(2^x+1)/(2^x-1)]/2
f(x)=f(-x)
所以是偶函数
f(x)=x*[1/(2^x-1)+1/2]
=x*[(2+2^x-1)/[2(2^x-1)]]
=x*[(2^x+1)/(2^x-1)]/2
f(-x)=(-x)*[(2^(-x)+1)/(2^(-x)-1)]/2
=(-x)*[(1+2^x)/(1-2^x)]/2
=x*[(2^x+1)/(2^x-1)]/2
f(x)=f(-x)
所以是偶函数