For positive integers, which of the following nth-term formulas represents an arithmetic progression (AP)?
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Answer and explanation
Correct answer: \(a_n=7-3n\)
In option A, \(a_{n+1}-a_n=[7-3(n+1)]-(7-3n)=-3\), which is constant for every \(n\); hence it is an AP. In option B, the difference changes. Exam tip: always test consecutive-term differences.
Frequently asked questions
What is the correct answer to this question?
\(a_n=7-3n\)
Why is this the correct answer?
In option A, \(a_{n+1}-a_n=[7-3(n+1)]-(7-3n)=-3\), which is constant for every \(n\); hence it is an AP. In option B, the difference changes. Exam tip: always test consecutive-term differences.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Arithmetic Progressions (AP). Topic: Finding the $n$th term of an AP.
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