Turn on thread page Beta
    • Thread Starter
    Offline

    13
    ReputationRep:
    What is the nth term of:
    12,26,46,72,104,142
    this is my cousins homework and shes so confused.
    thanks
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Selgomez11)
    What is the nth term of:
    12,26,46,72,104,142
    this is my cousins homework and shes so confused.
    thanks
    The differences are 14, 20, 26, 32, ... and the second differences are 6, 6, 6, 6, ...

    The second difference is constant which makes this a quadratic sequence.

    Quadratic sequences have nth term of the form an^2+bn+c, where a is the second difference divided by 2.

    So a = 6/2 = 3 and the nth term is 3n^2 + bn + c.

    Can you find b and c?
    • Community Assistant
    Offline

    20
    ReputationRep:
    Community Assistant
    (Original post by Selgomez11)
    What is the nth term of:
    12,26,46,72,104,142
    this is my cousins homework and shes so confused.
    thanks
    This isn't a homework service. What does she know anything about quadratic sequences?
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 17, 2013

University open days

  • Heriot-Watt University
    School of Textiles and Design Undergraduate
    Fri, 16 Nov '18
  • University of Roehampton
    All departments Undergraduate
    Sat, 17 Nov '18
  • Edge Hill University
    Faculty of Health and Social Care Undergraduate
    Sat, 17 Nov '18
Poll
Have you ever experienced bullying?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Equations

Best calculators for A level Maths

Tips on which model to get

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.