ARITHMETIC PROGRESSION
Analysis
 
4. GENERAL OR NTH TERM IN AN ARITHMETIC PROGRESSION

We can always find a formula which allows us to find any term in any arithmetic progression, as long as we know its position in the sequence. This formula is denoted as the general or nth term of the arithmetic progression.

9.- Examine the sequence in the window by going through the following steps:

step_1

Note that each term is equal to the preceding term plus the common difference.
(Check this by changing the value of n)
step_2

Note that all terms can be expressed in terms of the first term.
(Change the value of n)

Note the relationship between the position of each term and the number the common difference is multiplied by.
(Change the value of n)

Find the general or nth term of the sequence in the example. Try different sequences and find a general formula for any sequence.
step_3 Show the general term.

General term

an= a1+(n-1)*d
 
5. DETERMINING THE GENERAL TERM OF AN ARITHMETIC PROGRESSION

We are going to find the general or nth term of the following arithmetic progressions.

10.- Copy the following arithmetic progressions into your exercise book and work out the general term:

Terms a1 d an
3, 7, 11, 15, ...      
-12, -9, -6, -3, ...      
12, 9, 6, 3, ...      
6, 6, 6, 6, ...      
10, 3, -4, 11, ...      
120, 152, 184, ...      

Write down the first term a1 and the common difference d in each case, apply the general formula and carry out the operations indicated.

The results can be checked in the window.
       
           
  Juan Madrigal Muga
 
Spanish Ministry of Education. Year 2002
 
 

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