If (a_n=n^3-1), what is the value of (a_3)?
Answer and explanation
Correct answer: 26
Given \(a_n=n^3-1\). Substituting \(n=3\), we get \(a_3=3^3-1=27-1=26\). Therefore, 26 is correct. The close distractor 27 is only \(3^3\); the subtraction of 1 must still be done. Exam tip: For a sequence term, substitute the required index in the rule before calculating.
Frequently asked questions
What is the correct answer to this question?
26
Why is this the correct answer?
Given \(a_n=n^3-1\). Substituting \(n=3\), we get \(a_3=3^3-1=27-1=26\). Therefore, 26 is correct. The close distractor 27 is only \(3^3\); the subtraction of 1 must still be done. Exam tip: For a sequence term, substitute the required index in the rule before calculating.
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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