Turn on thread page Beta
    • Thread Starter
    Offline

    1
    ReputationRep:
    In the OCR core 3 exam.

    For a question like (3x+4)^5

    Would you have to show all working out with the u-substitution or can you do the short way of the power times the differential of the bracket times the bracket with a reduced power?

    Will you lose marks by using the short method?
    • Community Assistant
    Offline

    20
    ReputationRep:
    Community Assistant
    You can just write down the answer for something as simple as that.
    Offline

    16
    ReputationRep:
    i would just do y=(3x+4)^5

    => dy/dx= 15(3x+4)^4

    As you can work it out in your head (without to much thought) you don't need to write it all out. If there are lots of substitutions or more complex functions id write it all out just to make sure i get it right.
    • Thread Starter
    Offline

    1
    ReputationRep:
    Can I use the total marks as some form of indication as to whether I have to show all working then?

    e.g. if it is over 4 marks I should do it in full?
    Offline

    14
    ReputationRep:
    (Original post by kkid106)
    Can I use the total marks as some form of indication as to whether I have to show all working then?

    e.g. if it is over 4 marks I should do it in full?

    You ONLY have to show necessary working , provided that your method is clear.
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by steve2005)
    You ONLY have to show necessary working , provided that your method is clear.
    But how is necessary defined?
    • Community Assistant
    Offline

    20
    ReputationRep:
    Community Assistant
    (Original post by kkid106)
    Can I use the total marks as some form of indication as to whether I have to show all working then?

    e.g. if it is over 4 marks I should do it in full?
    If the question specifies a particular method then you must use that method. Otherwise it is entirely up to you.
    Offline

    14
    ReputationRep:
    (Original post by kkid106)
    But how is necessary defined?

    Just work out the problem. Remember that the examiner is more experienced than you and will be familiar with the answer, DON'T employ magic, don't work out the answer on the desktop or on plotting paper.

    An honest answer is all that is necessary.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: December 31, 2012

University open days

  • Southampton Solent University
    All faculties Undergraduate
    Sun, 18 Nov '18
  • University of Bradford
    All faculties Undergraduate
    Wed, 21 Nov '18
  • Buckinghamshire New University
    All Faculties Postgraduate
    Wed, 21 Nov '18
Poll
Black Friday: Yay or Nay?
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.