思路：根式化为分数指数幂；
原式=a^(1/2)*[a^(1/2)]^(1/2)*{[a^(1/2)]^(1/2)]}^(1/2)*a^(-1)
=a^(1/2)*a^(1/4)*a^(1/8)*a^(-1)=a^(1/2+1/4+1/8-1)=a^(-1/8)
化简根号下a*根号a*根号a除以a,看图
思路：根式化为分数指数幂；
原式=a^(1/2)*[a^(1/2)]^(1/2)*{[a^(1/2)]^(1/2)]}^(1/2)*a^(-1)
=a^(1/2)*a^(1/4)*a^(1/8)*a^(-1)=a^(1/2+1/4+1/8-1)=a^(-1/8)