Results 1 to 5 of 5

Math Help - Equation help.

  1. #1
    Newbie
    Joined
    Aug 2009
    Posts
    7

    Equation help.

    The problem is:

    "The points A and B have coordinates (a,a^2) and (2b,4b^2) respectively. Determine the gradient of AB in it's simplest form."

    The equation for gradient that we use is  m=y^2-y^1 / x^2-x^1

    So this is what I've got so far

     m=y^2-y^1 / x^2-x^1
    m=4b^2-a^2 / 2b-a

    Can someone please show me how to work through it?

    Thanks.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,698
    Thanks
    454
    Quote Originally Posted by jumba View Post
    The problem is:

    "The points A and B have coordinates (a,a^2) and (2b,4b^2) respectively. Determine the gradient of AB in it's simplest form."

    The equation for gradient that we use is  m=y^2-y^1 / x^2-x^1

    \textcolor{red}{m=\frac{y_2 - y_1}{x_2 - x_1}}

    So this is what I've got so far

     m=y^2-y^1 / x^2-x^1
    m=4b^2-a^2 / 2b-a

    Can someone please show me how to work through it?

    Thanks.
    factor the numerator ...

    \frac{(2b-a)(2b+a)}{2b-a} = 2b+a \,\,\, ; \,\,\, a \ne 2b
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Jun 2009
    Posts
    660
    Thanks
    133
    Use the difference of two squares formula,  A^2 - B^2 = (A -B)(A + B) , on the top line and you can cancel the  2b - a term.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Aug 2009
    Posts
    7
    Thank-you very much skeeter and BobP. Can't believe I could notice that since teachers go on about factorising all the time.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    Joined
    Dec 2007
    From
    Ottawa, Canada
    Posts
    3,102
    Thanks
    68
    Quote Originally Posted by jumba View Post
    m=4b^2-a^2 / 2b-a
    Careful...brackets required: (4b^2-a^2) / (2b-a)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: April 11th 2011, 01:17 AM
  2. Partial differential equation-wave equation - dimensional analysis
    Posted in the Differential Equations Forum
    Replies: 3
    Last Post: August 28th 2009, 11:39 AM
  3. Replies: 2
    Last Post: May 18th 2009, 12:51 PM
  4. Replies: 2
    Last Post: April 28th 2009, 06:42 AM
  5. Replies: 1
    Last Post: October 23rd 2008, 03:39 AM

Search Tags


/mathhelpforum @mathhelpforum