用数学归纳法证明x^2n-y^2n能被x+y整除(思路清晰即可、不奢求具体步骤)

x^2n的意思是x的2n次方y^2n的意思是y的2n次方
2025-01-19 16:59:17
推荐回答(3个)
回答1:

要证明这个(x^2n-y^2n)/X+Y因为X同Y的次数都系2N,所以,2N点都系整数将(x^2n-y^2n)/X+Y变成(X-Y)^2n/X+Y系前面加一个减号,所以就变成-(X+Y)^2n/X+Y所以变成--(X+Y)^2n-1如果你睇五明,你加我QQ啦,系电脑不知点表达除号,同埋次方号,所以,睇埋去比较难体啊。敬请原谅。哈哈。

回答2:

当n=1时,
x^2n-y^2n=x�0�5-y�0�5=(x+y)(x-y)
结论成立
现假设当n=k时,结论成立,即x^2k-y^2k能被x+y整除.无妨设x^2k-y^2k=M(x+y).

x^2(k+1)-y^2(k+1)
=x^(2k+2)-y^(2k+2)
=x�0�5x^2k-y�0�5y^2k
=x�0�5x^2k-x�0�5y^2k+x�0�5y^2k-y�0�5y^2k
=x�0�5(x^2k-y^2k)+(x�0�5-y�0�5)y^2k
=x�0�5M(x+y)+(x+y)(x-y)y^2k
=(x+y)[x�0�5M+(x-y)y^2k]
n=1 时,易证设 n=k 时,x^2k-y^2k 能被x+y 整除n=k+1 时,x^2(k+1)-y^2(k+1)=(x^2k-y^2k)(x^2k+y^2k)能被x+y 整除得证

回答3:

x�0�5-y�0�5=(x+y)(x-y) 所以:x�0�5-y�0�5能被x+y整除x的4次方-y的4次方=(x�0�5-y�0�5)(x�0�5+y�0�5)所以:x的4次方-y的4次方能被x+y整除.......x^2n-y^2n=(x的n次方-y的n次方)(x的n次方+y的n次方) x^2n-y^2n被x+y整除