write an expression for the nth term
asked Sep 13 in Other Math Topics by anonymous

Your answer

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
To avoid this verification in future, please log in or register.

1 Answer

There is a common difference of 2. For the nth term a₁=7, a₂=9, a₃=11, a₄=13, a₅=15 where n goes from 1 to 5. Subtract 1 from each term: 6, 8, 10, 12, 14. Now halve each: 3, 4, 5, 6, 7, which is 1+2, 2+2, 3+2, 4+2, 5+2.

So, by reversing the operations, a[n] (meaning a sub n)=2(n+2)+1=2n+5. (The reverse of ½ is 2 and the reverse of subtract is add.) Check: if n=1 a₁=2×1+5=7; n=2, a₂=2×2+5=9.

Therefore a[n]=2n+5.

 

answered Sep 14 by Rod Top Rated User (570,580 points)

Related questions

1 answer
1 answer
3 answers
1 answer
asked Mar 19, 2015 in Algebra 2 Answers by anonymous | 271 views
1 answer
Welcome to MathHomeworkAnswers.org, where students, teachers and math enthusiasts can ask and answer any math question. Get help and answers to any math problem including algebra, trigonometry, geometry, calculus, trigonometry, fractions, solving expression, simplifying expressions and more. Get answers to math questions. Help is always 100% free!
81,479 questions
85,659 answers
2,171 comments
69,137 users