Question

The explicit formula

of an geometric
sequence is
an = 0.5(-0.2)n-1
Write the recursive
formula using the
a1=
an=an-1 . R
Then write the first 4 terms of the sentence

Answer 1

Below.

Explanation:

{ a1 = 0.5

{ an = an-1*(-0.2)

The first 4 terms are:

= 0.5, -0.1, 0.02, -0.004

Answer 2

Explanation:

`a_n=(1)/(2) *((-1)/(5) )^(n-1)\\\\a_(n+1)=(1)/(2) *((-1)/(5) )^(n)\\\\\\\\(a_(n+1))/(a_n) =((1)/(2) *((-1)/(5) )^(n))/((1)/(2) *((-1)/(5) )^(n-1)) =(-1)/(5) \\a_1=(1)/(2) *((-1)/(5) )^(0)=(1)/(2) \\\\\\\boxed{a_1=(1)/(2)}\\\boxed{a_(n ) =-(1)/(5) *a_(n-1) }\\\\\\a_1=(1)/(2)\\\\a_2=(-1)/(10)\\\\a_3=(1)/(50)\\\\a_4=(-1)/(250)\\\\`