Question

Write an expression to describe the sequence below. Use n to represent the position of a term in the sequence, where n = 1 for the first term.
10, 11, 12, 13

Answer 1

Answer:

$9 + n$

Step-by-step explanation:

Well it's an arythmetic sequence, so it will look like:

$a + d\cdot n$

Note that the first element is:

$a + d\cdot 1$

and the second element is:

$a + d \cdot 2$

So the difference between the two gives us d!

$d = 11 - 10 = 1$

Now let's find the $a$:

$a + d\cdot 1 = 10\\a + 1 \cdot 1 = 10\\a + 1 = 10\\a = 9$