If (a_n=2n^2+9n+1), what is the value of (a_5)?
Answer and explanation
Correct answer: \(96\)
Given \(a_n=2n^2+9n+1\). Substituting \(n=5\), \(a_5=2(5)^2+9(5)+1=2\times25+45+1=96\). Hence, \(96\) is the correct option. A value such as \(94\) can result from an error while evaluating the squared term \(2\times25\). Exam tip: substitute the value of \(n\) first, then evaluate the exponent carefully.
Frequently asked questions
What is the correct answer to this question?
\(96\)
Why is this the correct answer?
Given \(a_n=2n^2+9n+1\). Substituting \(n=5\), \(a_5=2(5)^2+9(5)+1=2\times25+45+1=96\). Hence, \(96\) is the correct option. A value such as \(94\) can result from an error while evaluating the squared term \(2\times25\). Exam tip: substitute the value of \(n\) first, then evaluate the exponent 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.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
