Question

Find the first,fourth, and eighth terms of the sequence. A(n)=-5*2^n-1

Answer 1

`A(1)=-5*2^1-1=-11`

`A(1)=-5*2^4-1=-81`

`A(1)=-5*2^8-1=-1281`

Explanation:

Given :
`A(n)=-5*2^n-1`

To find :
`A(1), A(4), A(18)`

Solution:

Put n=1,
`A(1)=-5*2^1-1`

`A(1)=-10-1=-11`

Put n=4,
`A(1)=-5*2^4-1`

`A(1)=-80-1=-81`

Put n=8,
`A(1)=-5*2^8-1=`

`A(1)=-1280-1=-1281`

Answer 2

Answer:
`A(1)=-5`

`A(4)=-40`

`A(8)=-640`

Explanation:

Given sequence :
`A(n)=-5*2^(n-1)`

To find the first term, we need to put n=1 in the above sequence , we get

`A(1)=-5*2^(1-1)=-5*2^0=-5`

To find the fourth term, we need to put n=4, we get

`A(4)=-5*2^(4-1)=-5*2^3=-5*8=-40`

To find the eighth term, we need to put n=8, we get

`A(8)=-5*2^(8-1)=-5*2^7=-5*128=-640`