2004-3月178

winners

178. 数列1, 2,3,5,8,13,…(an=an-1+an-2)求s52=a1+a2+…+a52 橙子评价:感谢coolerdavid提供思路,a3=a2+a1,a4=a3+a2,a5=a4+a3....a54=a53+a52,change ta3-a2=a1,a4-a3=a2,a5-a4=a3....a54-a53=a52.the add both sides together.you will find s=a54-2.

a54=??

lololo

up!!!

linsonstudy

这题的答案就是a54－2吗？还是要算出具体的答案？