Results 1 to 7 of 7

Thread: Elasticity

  1. #1
    Member
    Joined
    Jul 2009
    Posts
    149

    Elasticity

    The price elasticity is given by

    $\displaystyle \epsilon = -\frac{p}{q}\cdot\frac{dq}{dp}$

    and the demand equation is given by
    $\displaystyle q = 700-35p $
    and p is given as 4 for $\displaystyle 0\leq p \leq 20 $

    So i plus in 4. Which gives q as 560.

    Then i take derivative of q which is 35? and derivative of p which is one?

    Then throw them in the elasticity equation and get -0.25.

    Does that make sense?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Jun 2009
    Posts
    671
    Thanks
    136
    The derivative of $\displaystyle q$ is -35, and you don't need the derivative of $\displaystyle p$; $\displaystyle p = 4.$
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Jul 2009
    Posts
    149
    so i have


    $\displaystyle \frac{4}{560}\cdot\frac{-35}{0}$


    That cant be right.

    if $\displaystyle p= \frac{700-q}{35}$

    then derivative of p is one?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Senior Member
    Joined
    Nov 2008
    Posts
    461
    Hi el123

    Quote Originally Posted by el123 View Post
    so i have


    $\displaystyle \frac{4}{560}\cdot\frac{-35}{0}$


    That cant be right.

    if $\displaystyle p= \frac{700-q}{35}$

    then derivative of p is one?
    According to BobP's statement

    it is
    $\displaystyle \epsilon = -\frac{p}{q}\cdot\frac{dq}{dp}$

    and the demand equation is given by
    $\displaystyle q = 700-35p $
    $\displaystyle \epsilon = - \frac{p}{q}*\frac{dq}{dp}$

    and

    $\displaystyle q = 700-35p $

    => $\displaystyle \frac{dq}{dp} = y' = -35$

    so $\displaystyle \epsilon = - \frac{p}{q}*\frac{dq}{dp} = - \frac{p}{q}*(-35)$

    Yours
    Rapha
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Super Member
    Joined
    Jun 2009
    Posts
    671
    Thanks
    136
    If $\displaystyle q = 700 -35p,$, then the derivative of $\displaystyle q$ wrt $\displaystyle p$ is

    $\displaystyle \frac{dq}{dp} = -35.$

    Also, if $\displaystyle q = 700 - 35p,$ then $\displaystyle p = \frac{700 - q}{35}$

    and the derivative of $\displaystyle p$ wrt $\displaystyle q$ would be

    $\displaystyle \frac{dp}{dq} = -\frac{1}{35}$,

    but that particular derivative is not needed.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member
    Joined
    Jul 2009
    Posts
    149
    indeed you are right.I see my mistake.

    Thanks guys ...or girls.

    One more thing , what does the ...for $\displaystyle 0 \leq p\leq 20 $ mean?
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Super Member
    Joined
    Jun 2009
    Posts
    671
    Thanks
    136
    It means that p is to be greater than or equal to zero, and less than or equal to 20.

    i.e. p has to lie within the range zero to 20 inclusive.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Need help on Elasticity
    Posted in the Business Math Forum
    Replies: 4
    Last Post: Dec 19th 2010, 02:13 AM
  2. elasticity of demand
    Posted in the Calculus Forum
    Replies: 7
    Last Post: Nov 9th 2010, 05:19 PM
  3. elasticity
    Posted in the Business Math Forum
    Replies: 0
    Last Post: Jan 28th 2010, 05:17 PM
  4. Elasticity
    Posted in the Calculus Forum
    Replies: 1
    Last Post: Apr 6th 2008, 01:10 PM
  5. Arc elasticity
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: Feb 12th 2008, 06:56 PM

Search Tags


/mathhelpforum @mathhelpforum