Hi again :)

I wonder why

Since one are suppose to always submit the whole problem:

Calculate curvelength.

I used:

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- July 24th 2009, 03:55 AMkallekallHelp understanding an integral rule
Hi again :)

I wonder why

Since one are suppose to always submit the whole problem:

Calculate curvelength.

I used: - July 24th 2009, 04:16 AMMoo
Hello,

Substitute

And you'll get the new integral :) - July 24th 2009, 05:27 AMkallekall
I didn't really manage to use your method but I called a friend and he said that curvelenght/area for always is equal to so I guess that I will just remeber that rule. But is that really true? What for

- July 24th 2009, 06:07 AMPlato
- July 24th 2009, 07:41 AMHallsofIvy
Moral, do not use rules you do not

**understand**!(Happy)

If f(x) is an**even**function, that is f(-x)= f(x), then , using the substitution u= -x.

So, again for an even function,

If f(x) is an**odd**function, that is f(-x)= -f(x), then , using the substitution u= -x.

Then, for an odd function, .

If f(x) is neither even nor odd, neither of those is true. - July 25th 2009, 03:50 AMkallekall
Thanks guys! You have helped me a lot!