Question

Write anexplicit formula for the following sequence. Find the twentieth term.16, 17, 18, 19, 20, ...

Answer 1

This is an arithmetic progression.

The first term is a and the common difference is 1.

The n-th term is

$T_{\N}=a+(n-1)d$$\begin{gathered} T_N=16+(n-1)1 \\ T_N=16+n-1 \\ T_N=15+n \end{gathered}$

To find the 20th term, put in 20 in place of n

$T_{20}=15+20\text{ = 35}$

The 20th term is 35