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The \(n\)th term of an arithmetic progression is \(a_n=7-2n\). Which option correctly identifies its first term and common difference?
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Answer and explanation
Correct answer: First term \(5\), common difference \(-2\)
In the standard form \(a_n=a+(n-1)d\), \(7-2n=5+(n-1)(-2)\). Hence, the first term is 5 and the common difference is −2. A negative \(d\) indicates a decreasing AP. Exam tip: verify the first term by putting \(n=1\).
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What is the correct answer to this question?
First term \(5\), common difference \(-2\)
Why is this the correct answer?
In the standard form \(a_n=a+(n-1)d\), \(7-2n=5+(n-1)(-2)\). Hence, the first term is 5 and the common difference is −2. A negative \(d\) indicates a decreasing AP. Exam tip: verify the first term by putting \(n=1\).
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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