g(x)=lg【(x²+2x+3)/(x+1)】分母不为零,x≠-1g(x)=lg【(x²+2x+3)/(x+1)】= lg【(x+1)(x+2)】= lg【(x+2)】单调增,g(1) = lg（1+2） = lg3,g(2) = lg（2+2） = 2lg2在[1,2]上的值域【lg3,2lg2】...