因为f(x)是奇函数,所以:f(x)=-f(-x)
a-1/(2^x+1)=-a+1/(2^-x+1)
2a=1/(2^x+1)+1/(2^-x+1)
2a=1/(2^x+1)+2^x/(1+2^x)
2a=(1+2^x)/(2^x+1)
2a=1
a=1/2
因为f(x)是奇函数,所以:f(x)=-f(-x)
a-1/(2^x+1)=-a+1/(2^-x+1)
2a=1/(2^x+1)+1/(2^-x+1)
2a=1/(2^x+1)+2^x/(1+2^x)
2a=(1+2^x)/(2^x+1)
2a=1
a=1/2