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Question
The nth term of a sequence is 8 – 5n. Show that the sequence is an A.P.
Solution
tn = 8 – 5n
Replacing n by (n + 1), we get
tn+1 = 8 – 5(n + 1)
= 8 – 5n – 5
= 3 – 5n
Now,
tn+1 – tn = (3 – 5n) – (8 – 5n) = –5
Since, (tn+1 – tn) is independent of n and is therefore a constant.
Hence, the given sequence is an A.P.
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