Results 1 to 3 of 3

Math Help - Function Problem

  1. #1
    Newbie
    Joined
    Oct 2012
    From
    Washington
    Posts
    12

    Function Problem

    Here is the problem:

    Arthur is going for a run. From his starting point, he runs due east at 10 feet per second for 230 feet. He then turns, and runs north at 12 feet per second for 400 feet. He then turns, and runs west at 7 feet per second for 70 feet.

    Express the (straight-line) distance from Arthur to his starting point as a function of t, the number of seconds since he started.

    Function Problem-screen-shot-2012-10-10-10.56.23-pm.png

    I can't figure out what I am doing wrong for the third part? Thank you!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2012
    From
    Australia
    Posts
    3,802
    Thanks
    656

    Re: Function Problem

    Hey UWM120.

    So for this problem, I am going to work out the hypotenuse of the triangle where the sides are the distance of the x and y positions.

    So we start off with a east distance of 230 but we need to subtract the distance based on the fact that the runner is now travelling west. So the difference squared for the x distance (i.e. find the distance and square it for pythagoras) is (230 - 7t)^2.

    Now for the y-distance, we know the guy is only running west so the y-distance doesn't change. The y-distance when the runner started running is 400 so the square is 400^2.

    Now the hypotenuse is just the square root of the sum of squares which is

    = SQRT(400^2 - (230 - 7t)^2)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2012
    From
    Washington
    Posts
    12

    Re: Function Problem

    Quote Originally Posted by chiro View Post
    Hey UWM120.

    So for this problem, I am going to work out the hypotenuse of the triangle where the sides are the distance of the x and y positions.

    So we start off with a east distance of 230 but we need to subtract the distance based on the fact that the runner is now travelling west. So the difference squared for the x distance (i.e. find the distance and square it for pythagoras) is (230 - 7t)^2.



    Now for the y-distance, we know the guy is only running west so the y-distance doesn't change. The y-distance when the runner started running is 400 so the square is 400^2.

    Now the hypotenuse is just the square root of the sum of squares which is

    = SQRT(400^2 - (230 - 7t)^2)
    Ohhh okay I see now. Thank you very much!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 20
    Last Post: November 27th 2012, 05:28 AM
  2. Replies: 6
    Last Post: August 13th 2010, 01:03 AM
  3. 1 Word problem and 1 function problem
    Posted in the Algebra Forum
    Replies: 8
    Last Post: April 21st 2010, 08:01 AM
  4. Greatest integer function (=step function) problem
    Posted in the Math Topics Forum
    Replies: 5
    Last Post: June 7th 2009, 01:43 PM
  5. Function within a function problem
    Posted in the Calculus Forum
    Replies: 10
    Last Post: April 26th 2009, 03:49 PM

Search Tags


/mathhelpforum @mathhelpforum