Identify the Sequence 11 , 12 , 13 , 14 , 15

This is an arithmetic sequence since there is a common difference between each term. In this case, adding ${\displaystyle 1}$ to the previous term in the sequence gives the next term. In other words, ${\displaystyle a_n=a_1+d(n-1)}$.

This is the formula of an arithmetic sequence.

Substitute in the values of ${\displaystyle a_1=11}$ and ${\displaystyle d=1}$.

Multiply ${\displaystyle n-1}$ by ${\displaystyle 1}$.