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Hey everyone,
I need to find the points on a curve which is represented by y = x / x+1, where the tangent is parallel to x - y = 2!
I believe I would use the derivative rules, and most probably quotient rule to find derivative of first equation 1 But then after that I can not seem to go on! Any help please!
Haven't done that for a long time, but:
You have a function f(x)=x/(x+1)
and you want all the points on that function that have a tangent that is parallel to the line: x - y = 2 which is that same as y=x-2, so this line has a gradient of 1!
So you need to find the points on the function that have a gradient of 1.
To find the gradient of a point on your function, you need to diferentiate it.
f(x)=x/(x+1)
or
f(x)=g(x)/h(x)=x/(x+1)
f'(x)=g'(x)*h(x)-g(x)*h'(x)/h(x)*h(x)
f'(x)=1*(x+1)-x*1/(x+1)^2=1/(x+1)^2
And then solve for 1
1=1/(x+1)^2
and that's only true for x=0
I'm crossing my fingers on that one!
...and for x = -2Quote:
Originally Posted by opus
I knew it, missed that one again