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Homework Help: Finding the tangent equations of the curve

  1. Nov 11, 2012 #1
    1. The problem statement, all variables and given/known data

    Find the tangent equations to the curve y^2= x-1/x+1 at the points with x=2

    2. Relevant equations



    3. The attempt at a solution

    I tried to solve in order to y: y=sqrt((x-1)/(x+1))

    Then I derived to obtain the slope, but this is the part that I don't know if it is correct. Do I need to derive the equation to get the slope, and after getting the slope I substitute the x in the equation that I got to get the tangent equation? I'm stuck here

    Thanks in advance
    Last edited: Nov 11, 2012
  2. jcsd
  3. Nov 11, 2012 #2


    Staff: Mentor

    from reading your problem you should expect more than one point where x=2.

    Next when taking the sqrt you'll have two possible eqns y=+sqrt(...) and y=-sqrt(...)

    when you say derive do you mean doing the sqrt or differentiate as in differential calculus?
  4. Nov 11, 2012 #3
    as in differential calculus... but I'm not sure if that's the correct method :p I know I have to take the square out of y. So I'll have too possible equations. But after taking it, I don't know what to do. I'll get y = sqrt((x-1)/(x+1)) or y = -sqrt((x-1)/(x+1))
  5. Nov 11, 2012 #4


    Staff: Mentor

    whats the definition of derivative? isn't it the slope of a tangent line at that point?
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