The general term of a sequence is given by an = -4n + 15. Is the sequence an A.P. ? If so, find its 15th term and the common difference

Asked by  | 10th Nov, 2012, 11:20: AM

Expert Answer:

an=-4n+15
So,
an-1=-4(n-1)+15=-4n+15+4
 
So, an-an-1=-4= constant
Hence, the given sequence is AP.
 
Common difference d=-4
15th term, n=15
a15=-60+15=-45

Answered by  | 10th Nov, 2012, 12:49: PM

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