Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter
    Offline

    16
    ReputationRep:
    1)Does anyone know how to draw the graph y=x+(3/x)? What does the x do ?? 2) how do you sketch this? Y=(x+k)^2-9,k>0 thanks for the help I am really stuck
    • Thread Starter
    Offline

    16
    ReputationRep:
    Also could anyone explain this? Name:  IMAG0064.jpg
Views: 86
Size:  390.2 KB f3 I don't get which length I am supposed this find and I did this Attachment 473251473253
    Attached Images
     
    Offline

    19
    ReputationRep:
    y=(x+3)/x is the same as y=3/x +1
    • Very Important Poster
    Offline

    21
    ReputationRep:
    Very Important Poster
    (Original post by coconut64)
    1)Does anyone know how to draw the graph y=x+3/x? What does the x do ?? 2) how do you sketch this? Y=(x+k)^2-9,k>0 thanks for the help I am really stuck
    For your first question, you may wish to plug in numbers that give you nice outputs like x = 1, x = 0.5 etc and see if you can spot the shape, which is similar to 1/x.

    For your second question, think about the different distinct points on the graph (Where is the maximum/minimum, when is y =0, when is x =0?) and think about how that helps.
    Offline

    21
    ReputationRep:
    (Original post by coconut64)
    1)Does anyone know how to draw the graph y=x+3/x? What does the x do ?? 2) how do you sketch this? Y=(x+k)^2-9,k>0 thanks for the help I am really stuck
    Y = (x+3)/x is the same as y = 1 + 3/x (so is a translation. At this point consider Y = 3/x and draw the graph, what would happen if we add 1)

    The second queation is basically the same except with have k being added to x. First consider Y = x^2 -9 and plot this graph Using the interval [-3,3], what would happen if we add a number k to x? Try making k equals 2 and do the same thing as before, and compare both answers.
    • Thread Starter
    Offline

    16
    ReputationRep:
    (Original post by whydoidothis?)
    y=(x+3)/x is the same as y=3/x +1
    No I mean y=x+(3/x), thanks
    Offline

    14
    ReputationRep:
    find the intercepts then sketch the graph (pay careful attention to the function transformations to make sure you get the positions right). also to find the length of the tangents, just use Pythagoras' theorem.
    • Thread Starter
    Offline

    16
    ReputationRep:
    (Original post by kkboyk)
    Y = (x+3)/x is the same as y = 1 + 3/x (so is a translation. At this point consider Y = 3/x and draw the graph, what would happen if we add 1)

    The second queation is basically the same except with have k being added to x. First consider Y = x^2 -9 and plot this graph Using the interval [-3,3], what would happen if we add a number k to x? Try making k equals 2 and do the same thing as before, and compare both answers.
    Hi, it is x+(3/x )thanksr
    Offline

    15
    ReputationRep:
    (Original post by coconut64)
    Hi, it is x+(3+x)/x thanks
    Is it  y = x + 3/x or  y = x + (3+x)/x ? You have said both.
    Offline

    21
    ReputationRep:
    (Original post by ombtom)
    Is it  y = x + 3/x or  y = x + (3+x)/x ? You have said both.
    This has just got confusing
    Offline

    15
    ReputationRep:
    (Original post by kkboyk)
    This has just got confusing
    I initially thought it was  y = (x+3)/x
    • Thread Starter
    Offline

    16
    ReputationRep:
    (Original post by ombtom)
    Is it  y = x + 3/x or  y = x + (3+x)/x ? You have said both.
    Sorry, I just realise it is y=x+(3/x)
    • Thread Starter
    Offline

    16
    ReputationRep:
    (Original post by ombtom)
    I initially thought it was  y = (x+3)/x
    Sorry guys it is actually y=x+(3/X)
    Offline

    21
    ReputationRep:
    (Original post by coconut64)
    Sorry, I just realise it is y=x+(3)/x
    Try drawing y=x and y=3/x separate on the same graph to help you visualise
    • Thread Starter
    Offline

    16
    ReputationRep:
    (Original post by kkboyk)
    Y = (x+3)/x is the same as y = 1 + 3/x (so is a translation. At this point consider Y = 3/x and draw the graph, what would happen if we add 1)

    The second queation is basically the same except with have k being added to x. First consider Y = x^2 -9 and plot this graph Using the interval [-3,3], what would happen if we add a number k to x? Try making k equals 2 and do the same thing as before, and compare both answers.
    Why doyou make k =2?
    • Thread Starter
    Offline

    16
    ReputationRep:
    (Original post by SeanFM)
    For your first question, you may wish to plug in numbers that give you nice outputs like x = 1, x = 0.5 etc and see if you can spot the shape, which is similar to 1/x.

    For your second question, think about the different distinct points on the graph (Where is the maximum/minimum, when is y =0, when is x =0?) and think about how that helps.
    Thanks for the reply but how do you work out k?
    Offline

    21
    ReputationRep:
    (Original post by coconut64)
    Why doyou make k =2?
    Just to make you visualise what would happen for any values of k (it will translate to the left for every positive value of K)
    • Very Important Poster
    Offline

    21
    ReputationRep:
    Very Important Poster
    (Original post by coconut64)
    Thanks for the reply but how do you work out k?
    You don't - k is any positive number in this case (it says k>0) so it wants you to have things in terms of k.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: October 29, 2015
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?
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.