Derivatives using the Limit Definition How do I find the derivative of $\sqrt{x^2+3}$? I plugged everything into the formula but now I'm having trouble simplifying. 
$$\frac{\sqrt{(x+h)^2+3}-\sqrt{x^2+3}}{h}$$

Keaton's comment is very useful.  If you multiply the top and bottom of your expression by $\sqrt{(x+h)^2+3}+\sqrt{x^2+3}$, the numerator should simplify to $2xh+h^2$.  See if you can finish the problem after that.
