Question

Write an explicit formula for the sequence and find the first 5 terms

a1=100, r=-20
a1=10, r=-1

Answer 1

I'm assuming we're working with geometric sequences.

`a_1 = 100, r = -20`

`T_n = 100(-20)^(n - 1)`

`T_1 = 100, T_2 = -2000, T_3 = 40000, T_4 = -80000, T_5 = 16 000 000`


`a_1 = 10, r = -1`

`T_n = 10(-1)^(n - 1)`

`T_1 = 10, T_2 = -10, T_3 = 10, T_4 = -10, T_5 = 10`