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If (a_n=4^n+2n-5) then what is the value of (a_3)?
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Answer and explanation
Correct answer: 65
Given \(a_n=4^n+2n-5\), substitute \(n=3\): \(a_3=4^3+2(3)-5=64+6-5=65\). Therefore, 65 is correct. A value such as 63 can result from incorrectly evaluating or adding the \(2n\) term. Exam tip: substitute the term number into every part of the rule before simplifying.
Frequently asked questions
What is the correct answer to this question?
65
Why is this the correct answer?
Given \(a_n=4^n+2n-5\), substitute \(n=3\): \(a_3=4^3+2(3)-5=64+6-5=65\). Therefore, 65 is correct. A value such as 63 can result from incorrectly evaluating or adding the \(2n\) term. Exam tip: substitute the term number into every part of the rule before simplifying.
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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