[求助]本月 70

christinehsu

70.An=A1*A2*A3*...*An-1，已知An=t，问An+2等于多少。T^4

頭暈瞭.....
可以求知
An+1= A1*A2*......An-1*An
An+2= A1*A2*......An-1*An*An+1
可是 An+2=T^$
怎麼來的? 求助
謝謝

christinehsu

up

jqhsu

An=t=A1*...*An-1

An+1=(A1*...*An-1)*An=t^2

An+2=(A1*...*An-1)*An*An+1=t*t*t^2=t^4