Results 1 to 4 of 4

Math Help - graph function

  1. #1
    Member
    Joined
    Aug 2009
    Posts
    211

    graph function

    the first question i have is: the function of f is defined by f(x) = (1 - 2x)(1 + 2x). i know how to find where it crosses the x axis, but what method do i use to find the interception of the y axis?

    the second question is (note the info in the first question): the graph of y = f(x) is translated by one unit in the positive x-direction and 4 units in the positive y-direction to give the graph of y = g(x). find an expression for g(x) in the form ax^2 + bx + c, where a, b and c are integers.

    how would i go about tackling these questions? with particular attention to the second one if possible. thankyou,
    mark

    ps- the answer to the second is -4x^2 + 8x + 1
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Jun 2008
    Posts
    175
    To find where it cross the x-axis, you would have made y=0 to get your two corresponding points that the graph crossed the x-axis. To find where the function crosses the y-axis you do a similar thing and sub x=0 in and find y
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Aug 2009
    Posts
    211
    any help with the second question?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by mark View Post
    [snip]
    the second question is (note the info in the first question): the graph of y = f(x) is translated by one unit in the positive x-direction and 4 units in the positive y-direction to give the graph of y = g(x). find an expression for g(x) in the form ax^2 + bx + c, where a, b and c are integers.

    how would i go about tackling these questions? with particular attention to the second one if possible. thankyou,
    mark

    ps- the answer to the second is -4x^2 + 8x + 1
    f(x) = (1 - 2x)(1 + 2x) = 1 - 4x^2.

    f(x) \rightarrow g(x) = f(x - 1) = 1 - 4(x - 1)^2 = 1 - 4x^2 + 8x - 4 = -4x^2 + 8x - 3.

    g(x) \rightarrow h(x) = g(x) + 4 =  -4x^2 + 8x - 3 + 4 = -4x^2 + 8x + 1.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Using the graph of the Function
    Posted in the Calculus Forum
    Replies: 1
    Last Post: August 3rd 2010, 09:10 PM
  2. Graph the function y =(x-1)(x-5)
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: June 6th 2010, 02:09 PM
  3. Graph of Function
    Posted in the Algebra Forum
    Replies: 1
    Last Post: March 13th 2010, 09:21 PM
  4. graph of a function
    Posted in the Discrete Math Forum
    Replies: 0
    Last Post: November 2nd 2009, 02:45 PM
  5. Replies: 2
    Last Post: August 26th 2009, 04:51 AM

Search Tags


/mathhelpforum @mathhelpforum