## PeX 3 years ago Calculate using the definition of the derivative the derivative of y=1/(1+2x) and y=ln(x)

1. mathTalk

tough one

2. JamesJ

The first function should be straightforward. Just work through the algebra. Which definition are you using btw? A. (Leibniz) Limit h->0 of $$\frac{ f(x+h) - f(x)}{h}$$ B. (Newton) Limit x ->a of $$\frac{ f(x) - f(a)}{x - a}$$

3. JamesJ

The second function with log is not so easy at all and to do it we (inc. you!) will need some sense of how you have defined the function log in your course. There are few different ways to define it and that definition will inform how you calculate this derivative.

4. PeX

Thank you ! we are using the leibniz definition . i'm trying the second one but without success yet =]