Which option contains the first three terms formed by (a_n=2n^2-n+4)?
Answer and explanation
Correct answer: (5, 10, 19)
For the first three terms, substitute \(n=1,2,3\). Thus, \(a_1=2(1)^2-1+4=5\), \(a_2=2(2)^2-2+4=10\), and \(a_3=2(3)^2-3+4=19\). Therefore, the correct sequence is \((5, 10, 19)\). Option C cannot be correct because its first term is 6. Exam tip: when a general term is given, begin with \(n=1\) and calculate each term systematically.
Frequently asked questions
What is the correct answer to this question?
(5, 10, 19)
Why is this the correct answer?
For the first three terms, substitute \(n=1,2,3\). Thus, \(a_1=2(1)^2-1+4=5\), \(a_2=2(2)^2-2+4=10\), and \(a_3=2(3)^2-3+4=19\). Therefore, the correct sequence is \((5, 10, 19)\). Option C cannot be correct because its first term is 6. Exam tip: when a general term is given, begin with \(n=1\) and calculate each term systematically.
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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