Results 1 to 2 of 2

Math Help - continuity

  1. #1
    Junior Member
    Joined
    Mar 2006
    Posts
    40

    Post continuity

    Suppose air temp. is T (degrees F) and wind speed is v (mph). Then the equivalent windchill temp. is given by the function

    W(v) = T if 0 <=v<=4
    91.4 + (91.4-T)(.0203v -.304sqrt v - .474) if 4<v<45
    1.6T -55 if v>=45

    For T=30 degrees F, what wind speed corresponds to a windchill temp. of 0 degrees F?


    I assume in this problem that I would set the second equation (beginning with 91.4 +(91.4-T), to 0 and solve for v, but that approaches isn't working very well so far. Am I wrong in my approach to the solution?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,672
    Thanks
    302
    Awards
    1
    Quote Originally Posted by becky
    Suppose air temp. is T (degrees F) and wind speed is v (mph). Then the equivalent windchill temp. is given by the function

    W(v) = T if 0 <=v<=4
    91.4 + (91.4-T)(.0203v -.304sqrt v - .474) if 4<v<45
    1.6T -55 if v>=45

    For T=30 degrees F, what wind speed corresponds to a windchill temp. of 0 degrees F?


    I assume in this problem that I would set the second equation (beginning with 91.4 +(91.4-T), to 0 and solve for v, but that approaches isn't working very well so far. Am I wrong in my approach to the solution?
    Is your problem in how to solve for v? I get

    0=91.4+(91.4-30)(.0203v-.304 \sqrt v-.474)

    0 = 1.2464v-18.6656 \sqrt v+62.2964

    Let t = \sqrt v

    Then 0 = 1.2464t^2-18.6656t+62.2964

    Using the quadratic formula I get t = 9.9545 and t = 5.02087, which corresponds to v = 99.092 and v = 25.2092.

    The solution, then, is v = 25.2092, since that's inside the correct range for the formula.

    -Dan
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. continuity
    Posted in the Calculus Forum
    Replies: 5
    Last Post: April 20th 2011, 01:36 PM
  2. y=x^3 (continuity)
    Posted in the Differential Geometry Forum
    Replies: 2
    Last Post: May 16th 2010, 10:50 PM
  3. continuity
    Posted in the Differential Geometry Forum
    Replies: 5
    Last Post: April 9th 2010, 04:23 PM
  4. Continuity
    Posted in the Calculus Forum
    Replies: 1
    Last Post: November 7th 2009, 09:10 PM
  5. Continuity, Uniform Continuity
    Posted in the Calculus Forum
    Replies: 0
    Last Post: February 1st 2009, 08:36 PM

Search Tags


/mathhelpforum @mathhelpforum