If (a_n=4^n+n-3), what is the value of (a_4)?
Answer and explanation
Correct answer: 257
Given \(a_n=4^n+n-3\), substitute \(n=4\): \(a_4=4^4+4-3=256+4-3=257\). Therefore, 257 is correct. A value such as 255 can result from an error while evaluating the \(n-3\) part. Exam tip: after substitution in a general term, evaluate the exponent first and then perform addition and subtraction carefully.
Frequently asked questions
What is the correct answer to this question?
257
Why is this the correct answer?
Given \(a_n=4^n+n-3\), substitute \(n=4\): \(a_4=4^4+4-3=256+4-3=257\). Therefore, 257 is correct. A value such as 255 can result from an error while evaluating the \(n-3\) part. Exam tip: after substitution in a general term, evaluate the exponent first and then perform addition and subtraction carefully.
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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