Turn on thread page Beta
    • Thread Starter
    Offline

    8
    ReputationRep:
    Hi Guys,
    the question on the attachment seems like a stretch in y direction but the answer is a stretch by a factor of 1/10 in x direction. can anyone explain that to me please? thanks
    Attached Images
     
    Offline

    11
    ReputationRep:
    It is all from manipulation of logs. 1 = log 10 and hence we have log 10 + 2 log x = log 10 + log x^2 = log (10 times x^2.)

    Since our original function is 2log x = log (x^2). This is of the form of a transform f(x) to f(10x) and so is a stretch by a SF 1/10 in the x-direction
    • Thread Starter
    Offline

    8
    ReputationRep:
    (Original post by nerak99)
    It is all from manipulation of logs. 1 = log 10 and hence we have log 10 + 2 log x = log 10 + log x^2 = log (10 times x^2.)

    Since our original function is 2log x = log (x^2). This is of the form of a transform f(x) to f(10x) and so is a stretch by a SF 1/10 in the x-direction
    so in this kind of question you have to play around with the second equation till you get the first one? can't it be stretch in positive y direction as the whole function has been added by 1?
    Offline

    11
    ReputationRep:
    (Original post by Alen.m)
    so in this kind of question you have to play around with the second equation till you get the first one? can't it be stretch in positive y direction as the whole function has been added by 1?
    Not really as the case for transforming f(x) by a y stretch is kf(x) and a x stretch is f(kx). In a q like this you need to transform the function into a form like

    kf(x) (y sf k)
    f(kx) (x sf 1/k)
    f(x) + k (translate y by amount k)
    f(x+k) (translate x by amount -k)
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: May 24, 2016
Poll
Do you think parents should charge rent?
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

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.