What is the #n#th term of the arithmetic sequence 7, 5, 3, 1,...?

1 Answer
Dec 3, 2014

This is an arithmetic sequence since there is a common difference between each term.

In this case, adding #-2# to the previous term in the sequence gives the next term.

This is the formula of an arithmetic sequence. #a_n=a_1+d(n-1)#

If we want the first term we use the #7# as #a_1#, and we get #a_n=7-2(1-1)# which gives #7#.

If we want to find the second term, we use the #7# again for #a_1# and we get #a_n=7-2(2-1)#.

Notice how the #n# is the number of the term we want and, therefore, is how we find the #n^(th)# term.