解给你式子吧
f(1-x)+f(x)
=1/[4^(1-x)+2]+1/[4^(x)+2]
=1/[4^1/4^x+2]+1/[4^(x)+2]
=4^x/[4^1+2*4^x]+1/[4^(x)+2]
=4^x/2/[2+4^x]+1/[4^(x)+2]
=(4^x/2+1)/[4^(x)+2]
=1/2(4^x/2+2)/[4^(x)+2]
=1/2
即f(-6)+f(7)=1/2
f(-5)+f(6)=1/2
.
f(0)+f(1)=1/2
即f(-6)+f(-5)+f(-4)+•••+f(0)+•••+f(6)+f(7)
=6×(1/2)
=3.