Question

just wanna make sure one more time :)
Use the definition of f′(a) (derivative) to compute f′(a) when
f(x) =4/(x+1)
and a = 2:

* * which one should i use :
limX-->a = f(x)-f(a)/X-a

or

lim h-->0 = f(a+h)-f(a)/h

Answer 1

either.

Answer 2

the first method is making the distance between 2 points so close, that it's virtually the same point
the second method is making the time interval gap virtually 0.

Answer 3

thx