If (a_n=5^n), what is the value of (a_4)?
Answer and explanation
Correct answer: 625
The rule for the terms is \(a_n=5^n\). Substituting \(n=4\), we get \(a_4=5^4=5\times5\times5\times5=625\). Option 125 is the value of \(5^3\), so it is a close but incorrect distractor. Exam tip: in an explicit rule, substitute the required term number directly for \(n\).
Frequently asked questions
What is the correct answer to this question?
625
Why is this the correct answer?
The rule for the terms is \(a_n=5^n\). Substituting \(n=4\), we get \(a_4=5^4=5\times5\times5\times5=625\). Option 125 is the value of \(5^3\), so it is a close but incorrect distractor. Exam tip: in an explicit rule, substitute the required term number directly for \(n\).
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Explicit or general rule.
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