Results 1 to 6 of 6

Math Help - Calculus Graph Help - Interpretation

  1. #1
    Newbie
    Joined
    Sep 2012
    From
    South Africa
    Posts
    7

    Calculus Graph Help - Interpretation


    Please see link below:
    http://oi48.tinypic.com/flgfpy.jpg

    I know how to get 3.1. a & b but not c and d.

    I also need help with questions 3.2. , 3.6. , 3.7. and 3.8.

    I can do the rest myself

    3.1.
    (x+1) (x) (x-3)
    =x^2 + x +x^2 -3x
    = 2x^2 - 2x
    a=2 & b= -2

    That's all I can get.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Mar 2013
    From
    BC, Canada
    Posts
    100
    Thanks
    16

    Re: Calculus Graph Help - Interpretation

    (0,-6) will help you attain d (i.e. find f(0) ). It's a good attempt at 3.1, but you need to substitute points A, B, and C into f(x). Since you can obtain d, then you only have a,b, and c left. This means that you need 3 equations (hint: substitute A and C to get two). In order to get a 3rd equation, note that A is a critical point (read: do something with the derivative). This will get you a 3rd equation, and then use these three to find a,b, and c.

    3.2 is asking about the critical point B. Note that you find these with the first derivative.

    I only see up to 3.6 with the image link you provided.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Sep 2012
    From
    South Africa
    Posts
    7

    Re: Calculus Graph Help - Interpretation

    Ok, I've figured out how to get d. All I need is C and question 3.2.

    I've been trying for quite a while today but I can't seem to get it.

    Please give me a detailed explanation on how to get C and then 3.2.

    Don't worry about the other questions cos I've sorted them out already, just these two are bothering me.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Mar 2013
    From
    BC, Canada
    Posts
    100
    Thanks
    16

    Re: Calculus Graph Help - Interpretation

    Please explain how you found a,b, and d but not c. Whatever you did to find these, should be used to find c as well.

    Once you have found all a,b,c, and d, then 3.2 is just a critical point (i.e. take the derivative and solve for x).
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Sep 2012
    From
    South Africa
    Posts
    7

    Re: Calculus Graph Help - Interpretation

    (x+1) (x) (x-3)
    =x^2 + x +x^2 -3x
    = 2x^2 - 2x
    a=2 & b= -2

    that's how I got A & B

    d= 6x -6
    6(0) -6
    = -6 (I substituted the 0 from the graph into the equation)

    If this is the wrong method please explain the correct one.

    Update:
    I think I have 3.2. now

    ax^3 +bx^2 + c
    = 2x^3 - 2x^2 - 10
    = 6x^2 -4x -10
    =3x^2 - 2x - 5
    =(3x -5) (x+1)
    x = 5/3 or -1

    I know I take 5/3 because it is positive and B is on that side of the graph but how do I get the Y value? is it -10 because of c?
    Last edited by VegetaZA; March 10th 2013 at 08:06 AM.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member
    Joined
    Mar 2013
    From
    BC, Canada
    Posts
    100
    Thanks
    16

    Re: Calculus Graph Help - Interpretation

    Quote Originally Posted by VegetaZA View Post
    (x+1) (x) (x-3)
    =x^2 + x +x^2 -3x
    = 2x^2 - 2x
    a=2 & b= -2
    This is incorrect since 2x^2 - 2x is not in the form of f(x).

    that's how I got A & B

    d= 6x -6
    6(0) -6
    = -6 (I substituted the 0 from the graph into the equation)

    If this is the wrong method please explain the correct one.

    Update:
    I think I have 3.2. now

    ax^3 +bx^2 + c
    = 2x^3 - 2x^2 - 10
    = 6x^2 -4x -10
    =3x^2 - 2x - 5
    =(3x -5) (x+1)
    x = 5/3 or -1

    I know I take 5/3 because it is positive and B is on that side of the graph but how do I get the Y value? is it -10 because of c?
    I don't follow your reasoning in the line of expressions above. You have three lines of differing polynomials, but I cannot determine where these came from. Again, you must use the fact that A is also a critical point, and also perhaps, that it is a double root (if you are going to take the factorization to f(x) route).
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: December 17th 2011, 12:48 PM
  2. Replies: 5
    Last Post: August 12th 2011, 02:02 AM
  3. Scatter Graph interpretation help :)
    Posted in the Statistics Forum
    Replies: 0
    Last Post: February 28th 2010, 05:33 AM
  4. Limits Graph Interpretation
    Posted in the Calculus Forum
    Replies: 4
    Last Post: June 7th 2008, 01:42 PM
  5. Calculus Graph
    Posted in the Calculus Forum
    Replies: 5
    Last Post: July 16th 2006, 03:38 PM

Search Tags


/mathhelpforum @mathhelpforum