Which formula is used to identify any term of an arithmetic progression when its first term and common difference are known?
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Answer and explanation
Correct answer: \(a_n=a+(n-1)d\)
The \(n\)th term is obtained by adding the common difference \(d\), \((n-1)\) times to the first term \(a\); hence \(a_n=a+(n-1)d\). Using \(a+nd\) adds one extra \(d\) even for the first term. Exam tip: put \(n=1\); the result must be \(a\).
Frequently asked questions
What is the correct answer to this question?
\(a_n=a+(n-1)d\)
Why is this the correct answer?
The \(n\)th term is obtained by adding the common difference \(d\), \((n-1)\) times to the first term \(a\); hence \(a_n=a+(n-1)d\). Using \(a+nd\) adds one extra \(d\) even for the first term. Exam tip: put \(n=1\); the result must be \(a\).
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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