Results 1 to 4 of 4

Math Help - Need a function

  1. #1
    Member
    Joined
    Sep 2009
    Posts
    242
    Thanks
    1

    Need a function

    Hi,

    I need a function f(x) such that:

    f(1)=10
    f(2)=8
    f(3)=6
    f(4)=4
    f(5)=2
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member Dinkydoe's Avatar
    Joined
    Dec 2009
    Posts
    411
    I think what you want is a continuous function:

    But the function f(x) = 12-2x works
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,037
    Thanks
    883
    Quote Originally Posted by rainer View Post
    Hi,

    I need a function f(x) such that:

    f(1)=10
    f(2)=8
    f(3)=6
    f(4)=4
    f(5)=2
    plot these points on a graph ... note that the points will line up nicely.

    remember y = mx+b ?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member
    Joined
    Aug 2009
    From
    Israel
    Posts
    976
    If we assume that f is of the form f(x)=ax+b then a=\frac{f(x_1)-f(x_2)}{x_1-x_2} \equiv -2 ~ \forall x_1,x_2 \in \{1,2,3,4,5\} \implies a = -2

    Now, substitute into f(x) = -2x+b one of the given points. Namely, we can use (5,2) \Rightarrow f(5) = 2 \Rightarrow 2 = -2*5+b \Rightarrow b = 2+10 = 12 \implies f(x) = -2x+12
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 20
    Last Post: November 27th 2012, 06:28 AM
  2. Replies: 0
    Last Post: October 19th 2011, 05:49 AM
  3. Replies: 4
    Last Post: October 27th 2010, 06:41 AM
  4. Replies: 3
    Last Post: September 14th 2010, 03:46 PM
  5. Replies: 2
    Last Post: September 2nd 2010, 11:28 AM

Search Tags


/mathhelpforum @mathhelpforum