已知Y的2次方+3Y-1=0求Y的8次方-3Y+1的值
问题描述：
已知Y的2次方+3Y-1=0求Y的8次方-3Y+1的值
答
已知,Y^2+3Y-1 = 0 ,解得：Y = (-3±√13)/2 .第一种做法：Y^2 = -3Y+1 ；Y^4 = (-3Y+1)^2 = 9Y^2-6Y+1 = 9(-3Y+1)-6Y+1 = -33Y+10 ；Y^8 = (-33Y+10)^2 = 1089Y^2-660Y+100 = 1089(-3Y+1)-660Y+100 = -3927Y+1189 ...