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

    0
    ReputationRep:
    how do i find dy/dx of:

    (1)
    k) xcosy
    l) x^2 e^2y
    m) e^x y^2
    n) 1/y
    o) x/y^3

    (2)
    f) 2x^2 y and 5xy^2


    :confused:
    Offline

    2
    ReputationRep:
    What do you think the answers are? Remember that dy/dx is taking the derivative with respect to x.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by m:)ckel)
    What do you think the answers are? Remember that dy/dx is taking the derivative with respect to x.
    yeah i understand that
    like for example k is cosy - xsiny dy/dx
    but how/what method was used
    Offline

    0
    ReputationRep:
    (Original post by SeekerOfKnowledge)
    yeah i understand that
    like for example k is cosy - xsiny dy/dx
    but how/what method was used
    For things like that, you have to use implicit differentiation.

    For example, for x*cos(y), you have to use the product rule on it where the first function is x and the second is cos(y).

    From there, you get cos(y) + x * d/dx [cos(y)].

    For the part that is d/dx [cos(y)], you simply use the chain rule.

    -sin(y)*dy/dx - since dy/dx is the derivative of y.

    For the other questions, just follow the normal differentiation rules (especially the chain rule) and treat 'y' as a function of y whose derivative is dy/dx.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Would you rather give up salt or pepper?
    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
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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.