Turn on thread page Beta
    • Thread Starter
    Offline

    12
    ....
    Offline

    18
    ReputationRep:
    (Original post by years101)
    Attachment 618184for 4)

    i wrote down
    2x + 8x^-2

    dy/dx = 2 + -16x^-3

    made it equal to 0

    do I factorise now?
    Well, you don't need to factorize, but you do need to find where 2-16/x^3 = 0.
    • Community Assistant
    Online

    20
    ReputationRep:
    Community Assistant
    (Original post by years101)
    RDKGames
    You can factorise but there is no reason to realistically. Just set dy/dx=0 for the stationary point and find its coordinates, then determine its nature via second derivative.
    Offline

    15
    ReputationRep:
    ok....so you take the equation given in the question and you rearrange it so it becomes y= 2x + 8x^-2
    Then you differentiate it to dy/dx = -16x + 2
    Now you can equate it to zero and work out the value of x, i.e 1/8 or 0.125
    Then you have to make a table.

    Hth
    • Community Assistant
    Online

    20
    ReputationRep:
    Community Assistant
    (Original post by Batgirl98)
    ...
    Then you have to make a table.
    Incorrect derivative, but table for what...?
    Online

    20
    ReputationRep:
    if you enjoy factorising then go ahead

    x3 - 8 = ( x - a ) ( x2 + bx + c )

    where a,b,c are integers.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: February 9, 2017
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.