\ \

Step 1 : 

n^th term of an arithmetic sequence :

The n^th term of an arithmetic sequence is .

Where is the first term and d  is the common difference. 

Step 2 : 

The initial term is and common ratio is .

The n^th term of an arithmetic sequence is

Substitute and in above equation.

The n^th term of an arithmetic sequence is

Step 2 :

Substitute in

The fifty-first term of an arithmetic sequence is

Solution : 

The n^th term of an arithmetic sequence is

The fifty-first term of an arithmetic sequence is