(3+1)(3^2+1)(3^4+1).(3^2n+1)=?八上数学题,
问题描述：
(3+1)(3^2+1)(3^4+1).(3^2n+1)=?八上数学题,
答
(3十1)(3^2十1)(3^4十1)…(3^2n十1)
=(3-1)(3十1)(3^2十1)…(3^2n十1)÷(3-1)
=(3^2-1)(3^2十1)…(3^2n十1)÷2
=(3^2n-1)(3^2n十1)÷2
=(3^4n-1)/2