F(X)=-2X+A/2X+1是奇函数
F(-x)=-F(x)
F(-x)+F(x)=0
F(0)=0
-1+A=0
A=1
F(X)=-2^X+1/2^X+1
=-1+2/2^X+1
2^X单调递增,F(x)单调递减,通分化简,易证