log以64为底（1/8）的对数+5^-log以5为底（√2-1）的对数/（√2+1）
1/8=1/2^3=2^(-3)
64=2^6
所以log64(1/8)=lg(1/8)/lg64=lg2^(-3)/lg2^6=-3lg2/6lg2=-3/6=-1/2
5^[-log5（√2-1）]
=5^log5(√2-1)^(-1)
=(√2-1)^(-1)
=1/(√2-1)
=(√2+1)/(√2+1)(√2-1)
=(√2+1)/(2-1)
=√2+1
所以5^[-log5（√2-1）]/(√2+1)
=(√2+1)/(√2+1)
=1
所以原式=-1/2+1=1/2