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

    10
    ReputationRep:
    Can anyone show me how to solve this?
    I am not really sure where to even begin.

    Write a differential equation to express this:

    (a) The rate at which the volume of a sphere changes with radius is proportional to the square of the radius.
    Offline

    8
    ReputationRep:
    Differentiate the formula for the volume of a sphere with respect to the radius and then see what you get
    • Thread Starter
    Offline

    10
    ReputationRep:
    (Original post by wightsnowolf)
    Differentiate the formula for the volume of a sphere with respect to the radius and then see what you get
    I got 4pir^2, thanks.
    Offline

    8
    ReputationRep:
    That's right. So that shows that the rate of change of volume with respect to the radius is proportional to the radius squared, where the constant of proportionality is 4*pi

    Since it will be proportional if V ' = k (r^2)
 
 
 
  • 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
    Did TEF Bronze Award affect your UCAS choices?
    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

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