Results 1 to 7 of 7

Math Help - Linear Law

  1. #1
    Super Member
    Joined
    Dec 2009
    Posts
    755

    Linear Law



    My attempt at manipulating the equation

    y^2=e^{ax+4}
    2lny=(-ax+4)lne
    lny=\frac{(-ax+4)}{2}
    lny=\frac{-a}{2}x+2
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by Punch View Post


    My attempt at manipulating the equation

    y^2=e^{ax+4}
    2lny=(-ax+4)lne
    lny=\frac{(-ax+4)}{2}
    lny=\frac{-a}{2}x+2
    hi

    your equation is correct .

    gradient =-\frac{a}{2}=\frac{-4-b}{2} -- equation 1

    the y-intercept is 2 , so we know another point (0,2)

    gradient =-\frac{a}{2}=\frac{b-2}{2} -- equation 2

    so now you hv 2 equations , whats next ?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Joined
    Nov 2008
    From
    France
    Posts
    1,458
    You are right

    Using the point (4,-4) gives you the value for a
    -4 = -\frac{a}{2} \times 4 + 2

    Then using the point (2,b) gives you the value for b
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member
    Joined
    Dec 2009
    Posts
    755
    From lny=\frac{-a}{2}x+2, substituting the point (4,-4)

    I would have to take lny=ln(-4) which shows error 2 in the calculator.
    confused
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by Punch View Post
    From lny=\frac{-a}{2}x+2, substituting the point (4,-4)

    I would have to take lny=ln(-4) which shows error 2 in the calculator.
    confused
    ln y (the whole thing) is -4 not the y inside the ln .
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Super Member
    Joined
    Dec 2009
    Posts
    755
    Oh... This means, lny=\frac{-a}{2}x+2 is expressed as Y=mX+C where where Y is the y coordinate and X is the x-coordinate
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by Punch View Post
    Oh... This means, lny=\frac{-a}{2}x+2 is expressed as Y=mX+C where where Y is the y coordinate and X is the x-coordinate
    yes
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 7
    Last Post: October 10th 2011, 04:06 PM
  2. Replies: 1
    Last Post: August 1st 2011, 11:00 PM
  3. Replies: 5
    Last Post: September 6th 2010, 04:55 PM
  4. Regression fundamentals (linear, non linear, simple, multiple)
    Posted in the Advanced Statistics Forum
    Replies: 13
    Last Post: November 12th 2009, 07:47 AM
  5. Replies: 7
    Last Post: August 30th 2009, 11:03 AM

Search Tags


/mathhelpforum @mathhelpforum