已知x^4+ax^2+1能被x^2+ax+1整除,确定a的值
1个回答

用分式除法做

x^2 -ax +(a-1+a^2)

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x^2+ax+1 | x^4+ ax^2 +1

|

| x^4+ax^3 +x^2

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| -ax^3 +(a-1)x^2 +1

| -ax^3 -a^2x^2 -ax

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| (a-1+a^2)x^2 +ax +1

| (a-1+a^2)x^2+(a-1+a^2)ax +(a-1+a^2)

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0

∵整除

∴a=(a-1+a^2)a 1=a-1+a^2

a^2+a-2=0

(a+2)(a-1)=0

a=-2 或a=1