问题
填空题
当n为任意实数,k为某一特定整数时,等式n(n+1)(n+2)(n+3)+l=(n2+kn+1)2成立.则k=______.
答案
n(n+1)(n+2)(n+3)+l,
=(n2+3n)(n2+3n+2)+l,
=(n2+3n)2+2(n2+3n)+l,
=(n2+3n+1)2,
∵(n2+kn+1)2=(n2+3n+1)2,
∴k=3,
故答案为:3.
当n为任意实数,k为某一特定整数时,等式n(n+1)(n+2)(n+3)+l=(n2+kn+1)2成立.则k=______.
n(n+1)(n+2)(n+3)+l,
=(n2+3n)(n2+3n+2)+l,
=(n2+3n)2+2(n2+3n)+l,
=(n2+3n+1)2,
∵(n2+kn+1)2=(n2+3n+1)2,
∴k=3,
故答案为:3.