If (a_n=4n^2+3), what is the value of (a_3+a_5)?
Answer and explanation
Correct answer: 142
Given \(a_n=4n^2+3\), \(a_3=4(3)^2+3=39\) and \(a_5=4(5)^2+3=103\). Therefore, \(a_3+a_5=39+103=142\). A value such as 140 can result from an error while squaring or adding. Exam tip: substitute each required value of \(n\) separately into the general term before finding their sum.
Frequently asked questions
What is the correct answer to this question?
142
Why is this the correct answer?
Given \(a_n=4n^2+3\), \(a_3=4(3)^2+3=39\) and \(a_5=4(5)^2+3=103\). Therefore, \(a_3+a_5=39+103=142\). A value such as 140 can result from an error while squaring or adding. Exam tip: substitute each required value of \(n\) separately into the general term before finding their sum.
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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