Results 1 to 2 of 2

Math Help - Need Help!

  1. #1
    Newbie
    Joined
    Nov 2007
    Posts
    6

    Need Help!

    i'm practicing for my upcomming exam and i found few problems that are related to the ch. we r studying. The problem is i dont know how to solve them, nor i have an answer. can any1 plz help and show step by step how to solve this problem. thnx in advance.
    here is the picture of the problems:
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by BryanK View Post
    i'm practicing for my upcomming exam and i found few problems that are related to the ch. we r studying. The problem is i dont know how to solve them, nor i have an answer. can any1 plz help and show step by step how to solve this problem. thnx in advance.
    here is the picture of the problems:
    this is pre-calculus? or did you post in the wrong forum?


    Here's how to start the first, the second is similar.

    The volume of a sphere is given by: V = \frac 43 \pi r^3

    differentiating implicitly with respect to time we get: \frac {dV}{dt} = 4 \pi r^2~ \frac {dr}{dt}

    now you are given r and \frac {dr}{dt} so just plug them in and solve for \frac {dV}{dt}


    the second is similar, just use the fact that V = \pi r^2 h
    Follow Math Help Forum on Facebook and Google+


/mathhelpforum @mathhelpforum