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If (a_n=n^3+2) then which term is equal to (66)?
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Answer and explanation
Correct answer: \(n=4\)
Given \(a_n=n^3+2\), set \(a_n=66\): \(n^3+2=66\), so \(n^3=64\). Since \(4^3=64\), \(n=4\) and hence \(a_4=66\). The close distractor \(n=3\) gives \(3^3+2=29\), not 66. Exam tip: subtract the constant first, then identify the cube root.
Frequently asked questions
What is the correct answer to this question?
\(n=4\)
Why is this the correct answer?
Given \(a_n=n^3+2\), set \(a_n=66\): \(n^3+2=66\), so \(n^3=64\). Since \(4^3=64\), \(n=4\) and hence \(a_4=66\). The close distractor \(n=3\) gives \(3^3+2=29\), not 66. Exam tip: subtract the constant first, then identify the cube root.
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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