lg根号60
=lg[(60)^(1/2)]
=1/2 *lg60
=1/2 *lg(6*10)
=1/2 *(lg10+lg6)
=1/2 *(1+lg6)
=1/2*[1+lg(2*3)]
=1/2*(1+lg2+lg3)
=1/2*(1+a+b)
故lg根号60开3次方=[1/2*(1+a+b)]^(1/3)