If (a_n=4^n-2), what is the value of (a_3)?
Answer and explanation
Correct answer: \(62\)
Given \(a_n=4^n-2\), substitute \(n=3\): \(a_3=4^3-2=64-2=62\). Hence, \(62\) is correct. The close distractor \(64\) is only the value of \(4^3\); the subtraction of \(2\) must still be done. Exam tip: substitute the term number first, then evaluate the exponent before subtracting.
Frequently asked questions
What is the correct answer to this question?
\(62\)
Why is this the correct answer?
Given \(a_n=4^n-2\), substitute \(n=3\): \(a_3=4^3-2=64-2=62\). Hence, \(62\) is correct. The close distractor \(64\) is only the value of \(4^3\); the subtraction of \(2\) must still be done. Exam tip: substitute the term number first, then evaluate the exponent before subtracting.
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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