Question

设a.b.x.y满足ax+by=3,ax^2+by^2=7,ax^3+by^3=16,ax^4+by^4=42,求ax^

Answer 1

答案是20。

因为(ax^2+by^2)*(x+y)=(ax^3+by^3)+xy(ax+by),所以有7(x+y)=16+3xy...(1)

因为(ax^3+by^3)*(x+y)=(ax^4+by^4)+xy(ax^2+by^2),所以有16(x+y)=42+7xy...(2)

因为(ax^4+by^4)*(x+y)=(ax^5+by^5)+xy(ax^3+b...