If (a_n=(2n-1)^2+2), what is the value of (a_5)?
Answer and explanation
Correct answer: 83
To find the fifth term, substitute \(n=5\) in the rule: \(a_5=(2\times5-1)^2+2=9^2+2=81+2=83\). Therefore, 83 is the correct option. The value 81 is only \(9^2\); the additional 2 in the rule must also be included. Exam tip: substitute the value of \(n\) first, then simplify brackets, powers, and addition in order.
Frequently asked questions
What is the correct answer to this question?
83
Why is this the correct answer?
To find the fifth term, substitute \(n=5\) in the rule: \(a_5=(2\times5-1)^2+2=9^2+2=81+2=83\). Therefore, 83 is the correct option. The value 81 is only \(9^2\); the additional 2 in the rule must also be included. Exam tip: substitute the value of \(n\) first, then simplify brackets, powers, and addition in order.
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.
