Darn professors....wish mine explained things...

How do I find f`(a) for$\displaystyle f(x) = (3x +1)^{1/2} $

Thats the square root of 3x+1, double thanks to someone who shows me how to put that in there.

I have only seen f(x) - f(a)/x-a and f(a + h) - f(a)/h, so no dx or whatever that stuff is please.