百度已知a+1/a=4,求a平方+1/a平方和a4 - 知识问答

百度已知a+1/a=4,求a平方+1/a平方和a4次方+1/a4次方的值

1个回答

a^2+1/a^2
=a^2+1/a^2+2-2
=(a+1/a)^2-2
=4^2-2
=16-2
=14
a^4+1/a^4
=a^4+1/a^4+2-2
=(a^2+1/a^2)^2-2
=14^2-2
=196-2
=194

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