a2-a1=4 a3-a2=6 a4-a3=8 a100=
1个回答
是不是缺个a1=?的条件?
a2-a1=4=2*2
a3-a2=6=2*3
a4-a3=8=2*4
……
an-a(n-1)=2*n
全部相加得
an-a1=2*(2+3+4+……+n)
相关问题
-4a^4-8a^3+6a+1-7a+2+6a^3+4a^4
给定100个实数a1,a2,……,a100,满足a1-4a2+3a3≥0,a2-4a3+3a4≥0,a3-4a4+3a5
a1+a2=1.a2+a3=2,a3+a4=3.a99+a100=100,那么a1+a2+a2+..+a100=多少?
记集合P={0,2,4,6,8},Q={m|m=100a 1 +10a 2 +a 3 ,a 1 ,a 2 ,a 3 ∈P
(a-2)(a-1)(a+3)(a+6)=-4a^2 3a^2+9a-4=?
若2a2-3a=6,则4a2-6a+100=______.
有一列数a1,a2,a3 ,a4,...,an,其中a1=6*2+1,a2=6*3+2,a3=6*4+3,a4=6*5+
比如:A1=3S+2;A2=4S+6,A3=8,A4=3,A5=3S,A6=10S,则B1=3*3+2;B2=4*3+6
(a1 - a2) * (a2 - a3) * (a3 - a4) * ...* (a99 - a100)
等比数列{an}的公比为q=-1/3,则(a1+2a3+3a5+4a7)/(a4+2a6+3a8+4a