A new calculus puzzler for you

• Feb 1st 2011, 12:31 PM
wonderboy1953
A new calculus puzzler for you
$\displaystyle \int(1 + sin^2x)^{1/2}dx$
• Feb 1st 2011, 01:02 PM
topsquark
$\displaystyle E(x|m) = \int(1 - m~sin^2x)^{1/2}dx$ is an elliptic integral. In this case m = -1. So there shouldn't be a closed form for this one?

-Dan
• Feb 1st 2011, 01:07 PM
wonderboy1953
Want to be sure
Quote:

Originally Posted by topsquark
$\displaystyle E(x|m) = \int(1 - m~sin^2x)^{1/2}dx$ is an elliptic integral. In this case m = -1. So there shouldn't be a closed form for this one?

-Dan

Just to be sure, if m were -1, would that imply the equation can be solved in closed form?
• Feb 1st 2011, 01:19 PM
TheCoffeeMachine
Quote:

Originally Posted by wonderboy1953
...

• Feb 1st 2011, 01:23 PM
wonderboy1953
Quote:

Originally Posted by TheCoffeeMachine

Don't have one which is why I posted in the puzzle section
• Feb 1st 2011, 01:40 PM
TheCoffeeMachine
Quote:

Originally Posted by wonderboy1953
Don't have one which is why I posted in the puzzle section

So you had $\displaystyle \int \sqrt{1+\sin^2{x}}\;{dx}$ which you couldn't do!
To get help with it you posted it in the puzzles section.
Why? Wasn't that the purpose of the calculus forum?
• Feb 1st 2011, 01:51 PM
wonderboy1953
Quote:

Originally Posted by TheCoffeeMachine
So you had $\displaystyle \int \sqrt{1+\sin^2{x}}\;{dx}$ which you couldn't do!
To get help with it you posted it in the puzzles section.
Why? Wasn't that the purpose of the calculus forum?

I don't attend school. I post items that potentially would be interesting. I like to keep my mind sharp by coming to MHF.

I'm not necessarily looking for help, just good conversation. It's easy to come up with puzzles with interesting answers and solutions (as I've already posted on other threads), and others that may have no (closed) solutions as the one I just posted.

Keep in mind I'm a math explorer and will delve into areas that I may not be totally familiar with. You have the option of passing up on my threads and find more worthwhile ones for you.
• Feb 1st 2011, 03:38 PM
topsquark
Quote:

Originally Posted by wonderboy1953
I don't attend school. I post items that potentially would be interesting. I like to keep my mind sharp by coming to MHF.

I'm not necessarily looking for help, just good conversation. It's easy to come up with puzzles with interesting answers and solutions (as I've already posted on other threads), and others that may have no (closed) solutions as the one I just posted.

Keep in mind I'm a math explorer and will delve into areas that I may not be totally familiar with. You have the option of passing up on my threads and find more worthwhile ones for you.

You know I had a Statistical Mechanics professor that once gave us an "extra credit" problem that couldn't be solved. I am feeling very much the same way to wonderboy53 as I was with him at the time.

This wasn't a "puzzle" it was merely an unsolved problem. I was looking forward to seeing the solution to this problem, dangit. Please post your problems in the correct forum. That or at least have the courtesy of telling us that you don't know how to solve it.

-Dan
• Feb 2nd 2011, 02:09 AM
mr fantastic
Quote:

Originally Posted by wonderboy1953
I don't attend school. I post items that potentially would be interesting. I like to keep my mind sharp by coming to MHF.

I'm not necessarily looking for help, just good conversation. It's easy to come up with puzzles with interesting answers and solutions (as I've already posted on other threads), and others that may have no (closed) solutions as the one I just posted.

Keep in mind I'm a math explorer and will delve into areas that I may not be totally familiar with. You have the option of passing up on my threads and find more worthwhile ones for you.

The question you posted may have been a 'puzzle for conversation' in your mind but to most other members there is a clear implication that you had a solution. The fact that you don't have a solution means that potentially many members will feel deceived. In light of what you have said, the question clearly should have been posted in the Calculus subforum.