(1)n(n+1)(n+2)(n+3)+1=(n²+3n+1)².
(n为正整数).证明如下:
n(n+1)(n+2)(n+3)+1
=【n(n+3)】【(n+1)(n+2)】+1
=(n²+3n)(n²+3n+2)+1
=(n²+3n)²+2(n²+3n)+1
=(n²+3n+1)².
(2)2000*2001*2002*2003+1
=(2000²+3*2000+1)²
= 4006001².
(1)n(n+1)(n+2)(n+3)+1=(n²+3n+1)².
(n为正整数).证明如下:
n(n+1)(n+2)(n+3)+1
=【n(n+3)】【(n+1)(n+2)】+1
=(n²+3n)(n²+3n+2)+1
=(n²+3n)²+2(n²+3n)+1
=(n²+3n+1)².
(2)2000*2001*2002*2003+1
=(2000²+3*2000+1)²
= 4006001².