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Solution Check

  • 05-05-2011 4:02pm
    #1
    Moderators, Education Moderators, Technology & Internet Moderators, Regional South East Moderators Posts: 24,056 Mod ✭✭✭✭


    Just want an extra set of eyes checking my solution for this;

    Let v(t) = 2ln(t)

    - Find the slop of the function at t=1
    - Find the equation of the tangent at t=1

    Part 1

    v(t) = 2ln(t)
    v'(t) = 2(1/t)
    = 2/t
    =2/1 = 2

    2 > 0 therefore slope is increasing at t=1

    Part 2

    Formula to calculate tangent:
    y-y1 = m(x-x1)

    Therefore I need (x1, y1) and m.

    To find my (x1, y1)..

    v(t) = 2ln(t)
    = 2ln(1)
    = 0

    Points are (1,0)

    Slope determined already in part 1 as 2.

    y-0 = 2[x-(1)]
    y-0 = 2x-2
    y = 2x-2+0

    I cant spot my error here, hoping for an extra pair of eyes to point out where I made the mistake. Thanks! :)


Comments

  • Moderators, Science, Health & Environment Moderators Posts: 1,852 Mod ✭✭✭✭Michael Collins


    Sully wrote: »
    Just want an extra set of eyes checking my solution for this;

    Let v(t) = 2ln(t)

    - Find the slop of the function at t=1
    - Find the equation of the tangent at t=1

    Part 1

    v(t) = 2ln(t)
    v'(t) = 2(1/t)
    = 2/t
    =2/1 = 2

    2 > 0 therefore slope is increasing at t=1

    Part 2

    Formula to calculate tangent:
    y-y1 = m(x-x1)

    Therefore I need (x1, y1) and m.

    To find my (x1, y1)..

    v(t) = 2ln(t)
    = 2ln(1)
    = 0

    Points are (1,0)

    Slope determined already in part 1 as 2.

    y-0 = 2[x-(1)]
    y-0 = 2x-2
    y = 2x-2+0

    I cant spot my error here, hoping for an extra pair of eyes to point out where I made the mistake. Thanks! :)

    I can't see any calulation errors, although I wouldn't say the "slope" is increasing at t = 1. The function is increasing alright, but the slope is, in fact, decreasing.


  • Moderators, Education Moderators, Technology & Internet Moderators, Regional South East Moderators Posts: 24,056 Mod ✭✭✭✭Sully


    Cheers, much appreciated!


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