Results 1 to 5 of 5

Math Help - Please - Need help tonight on a couple more calc problems

  1. #1
    Newbie
    Joined
    May 2006
    Posts
    4

    Please - Need help tonight on a couple more calc problems

    thanks
    Last edited by JohnSena; May 23rd 2006 at 11:54 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Global Moderator

    Joined
    Nov 2005
    From
    New York City
    Posts
    10,616
    Thanks
    10
    Quote Originally Posted by JohnSena
    1. Write an equation for the graph obtained by shifting the graph of y=x^3 vertically upward by 3 units, followed by vertically sketching the graph by a factor of 5.
    I guess,
    5(x^3+3)=5x^3+15
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    May 2006
    Posts
    4
    thanks for the quick answer
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Global Moderator

    Joined
    Nov 2005
    From
    New York City
    Posts
    10,616
    Thanks
    10
    Quote Originally Posted by JohnSena

    4. A standard cup of coffee contains about 100mg of caggeine, and caffeine leaves the body at a rate of about 17% per hour. Give a formula for the amount of caffeine in the body after t hours. How much caffeine is left in the body after 3 hours?
    This is an exponential problem since you remove 17% it is the same as saying 83% of the total amount thus,
    A(t)=100(.83)^t

    For the second part you need to find,
    100(.83)^3\approx 57.18
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by JohnSena

    2. A ball is thrown into the air at time t=0, and its height above ground (in feet) t seconds after it is thrown is given by f(t)=-16t^2+96t+6
    a) How long is it in the air?
    b) How high does it go?
    c) When does it reach its maximum height?
    a) the ball hits the ground when:

    <br />
f(t)=-16t^2+96t+6=0<br />

    This will have two roots, one positive and the other negative, the
    negative root is unphysical but the positive one is what you want.

    The roots are:

    <br />
-0.06186, 6.06186<br />

    So the ball is in the air \approx 6.06seconds.

    b) The maximum height is achieved when f(x) is
    a maximum. As this is a quadratic we know this occurs midway
    between the roots, so it occurs at (-0.06186+6.06186)/2=3,
    so the maximum height is:

    <br />
f(3)=16\ 3^2+96\ 3+6=438 feet.

    c) Already answered at t=3seconds.

    RonL
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Need help with a couple calc questions.
    Posted in the Calculus Forum
    Replies: 4
    Last Post: March 25th 2010, 11:52 AM
  2. Replies: 8
    Last Post: December 7th 2008, 01:45 PM
  3. A couple Calc 2 questions
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 19th 2008, 10:46 PM
  4. Replies: 31
    Last Post: May 17th 2008, 12:42 PM

Search Tags


/mathhelpforum @mathhelpforum