Bobby Armstrong wrote:
> Hello, i need help with this one pronlem,
>
> I need to know the derivative to this equation and the equation to the
line
> that crosses tan to point (0,1)
>
> f(x) = 1 / (x+1)
>
> The answer i keep getting i know isnt right as you can see or i wouldnt
be
> asking people on here.
>
> Thanks so much for the time,
> Bobby
>
>
You could use the quotient rule [1], that is
(u/v)' = (v*u' - u*v')/(v^2)
In your case, f(x) = 1/(x + 1), you can write u = 1 and v = (x + 1).
Therefore, we have u' = (1)' = 0 since u is a constant and
v' = (x + 1)'
= (x)' + (1)' -- Addition rule
= 1 + 0
= 1
Thus the derivative of f(x)is going to be
f'(x) = ((x + 1)*0 - 1*1)/(x + 1)^2 = -1/(x + 1)^2
HTH,
Jean-Marc
[1]
http://archives.math.utk.edu/visual.calculus/2/quotient_rule.4/index.html
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