# Thread: Length of a curve

1. ## Length of a curve

Hi, I need calculate the length of a curve. Could someone help me please?

Formula:

2. Well, what have you tried so far?

3. I can not derivative and exponentiate: (

4. You can't differentiate your function? Differentiation is like an onion: you have to peel back the layers, in inverse order in which you would compute. Let's say you take your function

$f(x)=\dfrac{1}{3}(x-3)\sqrt{x},$

and you want to find $f(3).$ List all the computations you must do, in order, in order to find this value.

5. That´s right?

derivate:

exponentiation:

6. No, I'm afraid your differentiation is incorrect. What differentiation rule do you have to use here?

7. Try writing $y= \frac{1}{3}(x- 3}\sqrt{x})$ as $y= \frac{1}{3}(x- 3)x^{1/2}= \frac{1}{3}x^{3/2}- \frac{1}{3}x^{1/2}$.