Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    Hi,

    Im struggling with the Matrices part of P6 I know how to times add subtract etc them but im stuggling with transformations, determinants of 3 x 3 matrices and inverses of matrices, if any revision websites or notes or points in the right direction would help me out SO MUCH.

    Many Thanks

    Streety
    Offline

    15
    ReputationRep:
    (Original post by streetyfatb)
    Hi,

    Im struggling with the Matrices part of P6 I know how to times add subtract etc them but im stuggling with transformations, determinants of 3 x 3 matrices and inverses of matrices, if any revision websites or notes or points in the right direction would help me out SO MUCH.

    Many Thanks

    Streety
    Is this edexcel? The edexcel matrix stuff is straightforward manipulation techiniques that simply need to be learned. Do you have a textbook for your syllabus?
    Offline

    0
    ReputationRep:
    (Original post by streetyfatb)
    Hi,

    Im struggling with the Matrices part of P6 I know how to times add subtract etc them but im stuggling with transformations,
    a few bits,
    1.they give you the general transformations for reflections and rotations in the formula book
    2. if the determinent is negative it is a reflection
    3. determinent gives you the area scale factor

    determinants of 3 x 3 matrices
    are you ok doing the vector product with vectors? its exactly the same thing but with a 3x3 grid of all numbers and not an i,j,k on the top

    and inverses of matrices,
    2x2 - swap leading diagonal values and make other 2 negative (from what they were) then divide whole by determinent of original matrix

    3x3 - label columns a,b, and c, do cross product on pairs, then put these into the rows of your new matrix in this order:
    bxc
    cxa
    axb
    then divide by determinent of original matrix

    Dont know if any that will help you, hope it does

    I'm dreading tomorrow

    Lucy x
    • Thread Starter
    Offline

    0
    ReputationRep:
    Hi thanks for that, the exam board is OCR and the exam is tomorrow, im taking P6, P3 and D1, im just dreading the matrice questions.
    Offline

    15
    ReputationRep:
    (Original post by streetyfatb)
    Hi thanks for that, the exam board is OCR and the exam is tomorrow, im taking P6, P3 and D1, im just dreading the matrice questions.
    Ahh, i see. From the little I know some of the OCR material is more complex than the edexcel so you probably do things I don't even know about...
    From the post by Ventricles I see you have a different method for finding the inverse of a matrix to that given in the P6 heinemann book. It seems much faster but i'll probably play safe and stick with my current method for my exam.
    Offline

    0
    ReputationRep:
    (Original post by Gaz031)
    Ahh, i see. From the little I know some of the OCR material is more complex than the edexcel so you probably do things I don't even know about...
    From the post by Ventricles I see you have a different method for finding the inverse of a matrix to that given in the P6 heinemann book. It seems much faster but i'll probably play safe and stick with my current method for my exam.
    We were actually taught a different method- where you put the identity next to the matrix and then turn the matrix into the identity using row additions etc. but we got upset and found the other method (Ventricles') which seems like quite a bit of working but works every time x
    Offline

    2
    ReputationRep:
    (Original post by Ventricles)
    a few bits,
    1.they give you the general transformations for reflections and rotations in the formula book
    2. if the determinent is negative it is a reflection
    3. determinent gives you the area scale factor

    Lucy x
    they give us the general thingys!! grrrrrrrrr y did no one tell me
    Offline

    14
    ReputationRep:
    (Original post by undercover-ange)
    We were actually taught a different method- where you put the identity next to the matrix and then turn the matrix into the identity using row additions etc. but we got upset and found the other method (Ventricles') which seems like quite a bit of working but works every time x

    Hmmmm; for a 2x2 obviously theres the standard method:

    A-1 = \frac{1}{ad-bc}\left(\begin{matrix}d&-b\\-c&a\end{matrix}\right).

    For 3x3 or bigger I have to admit to using Elementary Row/Column Operations on an augmented matrix:

    A | In ===> In | A-1
 
 
 
Turn on thread page Beta
Updated: June 6, 2005

University open days

  • University of Lincoln
    Mini Open Day at the Brayford Campus Undergraduate
    Wed, 19 Dec '18
  • University of East Anglia
    UEA Mini Open Day Undergraduate
    Fri, 4 Jan '19
  • Bournemouth University
    Undergraduate Mini Open Day Undergraduate
    Wed, 9 Jan '19
Poll
Were you ever put in isolation at school?
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.