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Homework Help: Beginning derivatives

  1. Sep 15, 2008 #1
    Find an equation for the tangent to the curve at the given point.

    y=2(sqrt(x)) point- (1,2)

    Ok so I think I can work most of it then I get stuck. I am not sure how you guys use the codes so I will try to type it out the best I can.

    lim = ( f(a+h)-f(a) ) / (h)
    = f(1+h)-f(1) / h
    = (2 sqrt(1+h) - 2) / h

    This is where I have gotten to. substituting in now will give me a 0 in my denominator. So where would I go next?
  2. jcsd
  3. Sep 15, 2008 #2


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    Gold Member

    Using the limit definition of the derivative is often quite tedious to actually find a derivative. Have you seen the result:

    [tex]\frac{d}{dx} x^n=nx^{n-1}[/tex]

    That will be much more useful for finding the derivative of your function.
  4. Sep 15, 2008 #3

    The teacher has not yet introduced us to that form to find the derivatives yet. He says thats the easy way. he just gave us the formula f(a+h)-f(a) / h and told us to use that until we actually get into derivatives.

    The answer is y = x+1
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