Question

Please help me ?

Answer 1

`E`

Explanation:

.

It is `E` because:

For `n=1`:

`a_1=3(1)(-1)^(1+1)=3(-1)^2=3(1)=3`

For `n=2`

`a_2=3(2)(-1)^(2+1)=6(-1)^3=6(-1)=-6`

For `n=3`

`a_3=3(3)(-1)^(3+1)=9(-1)^4=9(1)=9`

For `n=4`

`a_4=3(4)(-1)^(4+1)=12(-1)^5=12(-1)=-12`

Answer 2

`E`

Explanation:

`"substitute "n=1,2,3,4" into "a_n`

`n=color(red)(1)toa_(color(red)(1))=(3xxcolor(red)(1))(-1)^(color(red)(1)+1)=3xx1=3`

`n=color(red)(2)toa_(color(red)(2))=(3xxcolor(red)(2))(-1)^(color(red)(2)+1)=6xx-1=-6`

`n=color(red)(3)toa_(color(red)(3))=(3xxcolor(red)(3))(-1)^(color(red)(3)+1)=9xx1=9`

`n=color(red)(4)toa_(color(red)(4))=(3xxcolor(red)(4))(-1)^(color(red)(4)+1)=12xx-1=-12`

`Etoa_n=3n(-1)^(n+1)to{-3,6,-9,12}`