Originally Posted by

**infraRed** Hi. I'm trying to review stuff I learn in Calc I, and I'm up to derivatives. However, I'm stumped on this prob from my old book:

find derivative of 1/sqrt(x+2)

After putting it in the form lim(h->0) [(1/h)(f(x+h)-f(x))], substituting, and doing some algebra I end up with

lim(h->0)[(1/h)((sqrt(x+2)-sqrt(x+h+2))/(sqrt(x+h+2)*sqrt(x+2)))]

If I multiple by conjugate I get 2x+h+4 on the top, and something really compilicated on the bottom, and I'm still not clear on how to get rid of the 1/h. Please advise me on the correct approach.