Results 1 to 2 of 2

Math Help - What Am I doing wrong in trying to find the tangent to this parametric equ?(W/ANSWER)

  1. #1
    Junior Member
    Joined
    Aug 2012
    From
    Maryland
    Posts
    45

    What Am I doing wrong in trying to find the tangent to this parametric equ?(W/ANSWER)

    find the tangent to the curve at the point corresponding to the given value of the parameter

    x=e^(√t)
    y= t - ln t
    t = 1

    I found...

    dx/dt = (e√x)/(2x)
    dy/dt = 1 - (2t/t)

    then you do

    dy/dt / dx/dt

    I got -e from that. I plugged in my coordinates and got

    y-1 = -e(x-e)

    the book says -(2/e)x+3. How am I so off?

    Thanks guys. and no offense but it'd be cool if you could do an entire "debug" in one post instead of asking questions that I probly couldn't answer. Not trying to sound like a jerk but i'm just not the sharpest calc student on the planet so theres no point in wasting our time.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,130
    Thanks
    1012

    Re: What Am I doing wrong in trying to find the tangent to this parametric equ?(W/ANS

    x = e^{\sqrt{t}}

    \frac{dx}{dt} = \frac{e^{\sqrt{t}}}{2\sqrt{t}}

    y = t - 2\ln{t}

    \frac{dy}{dt} = 1 - \frac{2}{t}

    at t = 1, x = e , y = 1 , \frac{\frac{dy}{dt}}{\frac{dx}{dt}} = -\frac{2}{e}

    y - 1 = -\frac{2}{e} (x - e)

    finish it ...
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: November 4th 2011, 07:42 PM
  2. Replies: 2
    Last Post: November 15th 2010, 07:41 PM
  3. Replies: 4
    Last Post: October 20th 2010, 05:51 AM
  4. Is the answer provided wrong!?
    Posted in the Discrete Math Forum
    Replies: 3
    Last Post: January 29th 2010, 07:35 AM
  5. Wrong answer key or wrong me ?
    Posted in the Algebra Forum
    Replies: 2
    Last Post: July 2nd 2008, 05:42 AM

Search Tags


/mathhelpforum @mathhelpforum