# Beginning derivatives

1. Sep 15, 2008

### ur5pointos2sl

Find an equation for the tangent to the curve at the given point.

y=2(sqrt(x)) point- (1,2)

Ok so I think I can work most of it then I get stuck. I am not sure how you guys use the codes so I will try to type it out the best I can.

lim = ( f(a+h)-f(a) ) / (h)
h->0
= f(1+h)-f(1) / h
= (2 sqrt(1+h) - 2) / h

This is where I have gotten to. substituting in now will give me a 0 in my denominator. So where would I go next?

2. Sep 15, 2008

### danago

Using the limit definition of the derivative is often quite tedious to actually find a derivative. Have you seen the result:

$$\frac{d}{dx} x^n=nx^{n-1}$$

That will be much more useful for finding the derivative of your function.

3. Sep 15, 2008

### ur5pointos2sl

The teacher has not yet introduced us to that form to find the derivatives yet. He says thats the easy way. he just gave us the formula f(a+h)-f(a) / h and told us to use that until we actually get into derivatives.

The answer is y = x+1