Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    Hi everyone

    I am struggling to do some exercises on my math website. They do not have the answers
    Could anyone of you help me with these problems?

    http://gyazo.com/b548e8425832cc83606b001bab0473e9

    Thank you
    Offline

    15
    ReputationRep:
    i`ll do the first one so you can see what they`re after:

    the first one is asking you to take the output from f(x) and make that the input to g(x). - i.e. so you have g(4x)=2^{(4x)-3}

    (think of it as g(X) where X =f(x) )
    • Thread Starter
    Offline

    0
    ReputationRep:
    On the website this is the only one I got right. I am not sure how to do the second and third one. I was thinking for the second one 23x-9 I don't know sure how to get the right answer.


    (Original post by Hasufel)
    i`ll do the first one so you can see what they`re after:

    the first one is asking you to take the output from f(x) and make that the input to g(x). - i.e. so you have g(4x)=2^{(4x)-3}

    (think of it as g(X) where X =f(x) )
    Offline

    15
    ReputationRep:
    for the first one f(x)=4x so, f(g(x))=4(g(x)) and we just replace g(x) with 2^{x-3} giving: 4 \times 2^{x-3}=2^{2} \times 2^{x-3}=2^{x-3+2}=2^{x-1}

    h(g(x)) is a little trickier:


    \diaplaystyle h(x)=\frac{1}{2x} so, \diaplaystyle h(g(x))=\frac{1}{2(g(x))} and we just replace g(x) with 2^{x-3} giving: \diaplaystyle h(g(x))= \frac{1}{2 ( 2^{x-3})}= \frac{1}{2^{x-2}}= \frac{1}{2^{-(2-x)}}=2^{2-x}

    You try the others...(same principle - you want 2^(something))
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?
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.