Join TSR now and get all your revision questions answeredSign up now
    • Thread Starter
    Offline

    11
    ReputationRep:
    16x+4y-19=0?
    • Thread Starter
    Offline

    11
    ReputationRep:
    ?????
    Offline

    2
    ReputationRep:
    16x+4y-19=0
    differentiated is 16+4dy/dx+0

    dy/dx=-16/4
    Dy/dx=-4
    Offline

    19
    ReputationRep:
    If you've been asked to differentiate with respect to x, first rearrange so to that you get an equation starting with y=.

    Then, differentiate as normal.
    Offline

    3
    ReputationRep:
    (Original post by p29)
    16x+4y-19=0?
    Like the above said

    rearrange for y

    4y=19-16x
    y=19/4 -4x

    then differentiate and you've got an answer
    Offline

    1
    ReputationRep:
    You have two options.

    Differentiating dy by dx means with respect to x, in terms of y. However your equation has a term with respect to y inside.

    So the 'simple' solution is to re-arange for y.
    16x+4y-19=0
    y = 1/4(19-16x)

    dy/dx = -4

    now you have an equation in terms of y with respect to x. Which you can differentiate dy by dx.

    Otherwise (depending on if you've learned), you can differentiate implicitly, this isn't so much of an issue for your equation as it can be re-arrange fairly simply. However for equations that are a lot more complex, implicitly is the way to go.

    d [16x+4y-19] by dx
    16 + 4 dy/dx = 0
    4 dy/dz = -16
    dy/dx = -4

    so you now have the differential of -4
 
 
 
Poll
Which web browser do you use?
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

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.