 So if we want to find the derivative of square root 3 minus x from the definition, we'll set down our limit definition of the derivative. Now we need to find f of x plus h and f of x. So we'll write down our functions and what we'll do is we'll drop our independent variable x and leave behind an empty set of parentheses. And the important thing is whatever goes in one set of parentheses has to go in all of them. So we want f of x plus h, so we'll drop an x plus h into the parentheses. We also need f of x. We'll fill these in to our definition. Now to deal with the square roots we can multiply numerator and denominator by the conjugate. Those will be the same terms, but added instead of subtracted. So if we multiply the numerator, but we'll keep the denominator in factored form, we'll scroll down to give us a little bit more space. We'll clean up the algebra. We'll do more algebra. Scroll down a bit more. Do more algebra. And finally we can take limit and then do some more algebra.