a^2-3a+1=0 求a+1⼀a a^2+1⼀a^2 (a-1⼀a)^2的值

2024-11-06 19:17:04
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回答1:

^2-3a+1=0,即a^2+1=3a,两边同除以a得:a+1/a=3

a^2+1/a^2=(a+1/a)^2-2=3^2-2=7
(a-1/a)^2=a^2+1/a^2-2=7-2=5