Question

Helpo me if you know the answers

Answer 1

Given:

The nth term of a number sequence is
`n^2+2n`.

To find:

The first 3 terms and the 10th term.

Solution:

We have, nth term of a number sequence.

`a_n=n^2+2n`

For n=1,

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

`a_1=1+2`

`a_1=3`

For n=2,

`a_2=(2)^2+2(2)`

`a_2=4+4`

`a_2=8`

For n=3,

`a_3=(3)^2+2(3)`

`a_3=9+6`

`a_3=15`

For n=10,

`a_(10)=(10)^2+2(10)`

`a_(10)=100+20`

`a_(10)=120`

Therefore, the first three terms are 3, 8 and 15 respectively. The 10th term is 120.