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