写出下列数列{an}的前5项 a1=1,a(n+1)=an+3 a1=2,a(n+1)=2an a1=3,a2=6,a(n+2)=a(n+1)-an
问题描述:
写出下列数列{an}的前5项 a1=1,a(n+1)=an+3 a1=2,a(n+1)=2an a1=3,a2=6,a(n+2)=a(n+1)-an
答
1.
a1=1,a(n+1)=an+3,
a2=4
a3=7
a4=10
a5=13
2.
a1=2,a(n+1)=2an
a2=4
a3=8
a4=16
a5=32
3.
a1=3,a2=6,a(n+2)=a(n+1)-an
a3=3
a4=-3
a5=-6