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

http://www.sdilej.eu/pics/ce653c1004...5e0762a89e.JPG

Formula:

http://www.sdilej.eu/pics/876126889a...ec1106c34.jpeg

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- Dec 6th 2010, 08:22 AMsnopyLength of a curve
Hi, I need calculate the length of a curve. Could someone help me please?

http://www.sdilej.eu/pics/ce653c1004...5e0762a89e.JPG

Formula:

http://www.sdilej.eu/pics/876126889a...ec1106c34.jpeg - Dec 6th 2010, 08:26 AMAckbeet
Well, what have you tried so far?

- Dec 6th 2010, 09:20 AMsnopy
I can not derivative and exponentiate: (

- Dec 6th 2010, 09:31 AMAckbeet
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

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

and you want to find $\displaystyle f(3).$ List all the computations you must do, in order, in order to find this value. - Dec 6th 2010, 09:47 AMsnopy
Thatīs right?

derivate:

http://www.sdilej.eu/pics/0454ed704b...950ac22cc9.JPG

exponentiation:

http://www.sdilej.eu/pics/f7e5067972...85ffbdbb17.JPG - Dec 6th 2010, 09:49 AMAckbeet
No, I'm afraid your differentiation is incorrect. What differentiation rule do you have to use here?

- Dec 6th 2010, 11:24 AMHallsofIvy
Try writing $\displaystyle y= \frac{1}{3}(x- 3}\sqrt{x})$ as $\displaystyle y= \frac{1}{3}(x- 3)x^{1/2}= \frac{1}{3}x^{3/2}- \frac{1}{3}x^{1/2}$.