h'(x)=(a1-1)+2(a2-1)x+…+n(an-1)x^(n-1)
an-1=(4/3)^(n-1)
所以h'(x)=1+2*(4x/3)+…+n(4x/3)^(n-1)
h'(8/3)=1+2*(32/9)+.+n(32/9)^(n-1)
h'(x)=(a1-1)+2(a2-1)x+…+n(an-1)x^(n-1)
an-1=(4/3)^(n-1)
所以h'(x)=1+2*(4x/3)+…+n(4x/3)^(n-1)
h'(8/3)=1+2*(32/9)+.+n(32/9)^(n-1)