Question

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

Answer 1

Answer:

$A(1)=-5\times2^1-1=-11$

$A(1)=-5\times2^4-1=-81$

$A(1)=-5\times2^8-1=-1281$

Step-by-step explanation:

Given :     $A(n)=-5\times2^n-1$

To find :   $A(1), A(4), A(18)$

Solution:

Put n=1, $A(1)=-5\times2^1-1$

               $A(1)=-10-1=-11$

Put n=4, $A(1)=-5\times2^4-1$

                $A(1)=-80-1=-81$

Put n=8, $A(1)=-5\times2^8-1=$

               $A(1)=-1280-1=-1281$

Answer 2

Answer: $A(1)=-5$

$A(4)=-40$

$A(8)=-640$

Step-by-step explanation:

Given sequence : $A(n)=-5\times2^{n-1}$

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

$A(1)=-5\times2^{1-1}=-5\times2^0=-5$

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

$A(4)=-5\times2^{4-1}=-5\times2^3=-5\times8=-40$

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

$A(8)=-5\times2^{8-1}=-5\times2^7=-5\times128=-640$