(2)an= 1/n2。 ( 1)a2= 1/6，a3= 1/ 12，a4= 1/20
(2)an= 1/n*(n+ 1)3。 ( 1)an=4n-5
(2) A =
{
5,
n= 1
{
6n-2，n & gt=2
(3)an=
{
1,
n= 1
{
2*3^(n- 1),n>； =24.( 1)A(n+ 1)= 0.8 an+0.3 bn
(2)A(n+ 1)=0.8An+0.3Bn
= 0.8 A +0.3( 100 A)
= 0.5 amp +30. Typing is not easy. If you are not clear, you can leave a message and I will tell you more.