设1列数a1,a2,a3.a100任意3个相邻数之和是37,以知a2=25,a9=2x,a99=3-x,那么a100=多少
问题描述:
设1列数a1,a2,a3.a100任意3个相邻数之和是37,以知a2=25,a9=2x,a99=3-x,那么a100=多少
答
由题可知,可得a1=a(3n+1),a2=a(3n+2),a3=a(3n+3)
那么a1=a100,a3=a9=a99=2x=3-x即x=1,a1+a2+a3=37,a2=25,a3=2即可知a100=10