Question

The first two terms of an arithmetic sequence are `a_1 = 2` and `a_2 = 4`. What is `a_10`, the tenth term?

Answer 1

`color(indigo)(a_10 = 20`

Explanation:

`a_1 = 2, a_2 = 4`

Common Difference `d = a_2 - a_1 = 4 - 2 = 2`

nth term of an Arithmetic Sequence is given by the formula,

`a_n = a_1 + (n-1) * d`

Given `a_1 = 2, n = 10` and we found `d = 2`

`:. color(indigo)(a_10) = 2 + (10-1)*2 = 2 + 18 color(indigo)(= 20`