(1-3a)(1+3a)(1+9^2)(1+81a^4),其中a=-1/2
问题描述：
(1-3a)(1+3a)(1+9^2)(1+81a^4),其中a=-1/2
答
(1-3a)(1+3a)(1+9a^2)(1+81a^4),
=(1-9a^2)(1+9a^2)(1+81a^4)
=(1-81a^4)(1+81a^4)
=1-81²a^8
=1-6561/256
=-6305/256