Hi...

I didn't understand this at all...

could someone solve it and explain me how he did it?

http://img827.imageshack.us/img827/1821/65184366.jpg

Thank you!

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- Oct 24th 2010, 11:06 AMrectangleHow to prove this Inequality?
Hi...

I didn't understand this at all...

could someone solve it and explain me how he did it?

http://img827.imageshack.us/img827/1821/65184366.jpg

Thank you! - Oct 24th 2010, 11:33 AMJhevon
- Oct 24th 2010, 11:46 AMUnknown008
Introduce tan on both sides of the given equation:

.

This becomes:

Now, since and are positive, is also positive.

So, is positive. and less than 1

And the minimum of is zero, which occurs only when or , which is not the case.

Hence, we get

EDIT: A little too late... - Oct 24th 2010, 11:51 AMJhevon
- Oct 24th 2010, 11:54 AMrectangle
- Oct 24th 2010, 12:29 PMJhevon
- Oct 24th 2010, 12:37 PMrectangle
Thank you so much!!!

- Oct 24th 2010, 01:16 PMrectangle
- Oct 24th 2010, 02:37 PMJhevon
- Oct 24th 2010, 02:48 PMrectangle
- Oct 24th 2010, 04:12 PMArchie Meade
- Oct 24th 2010, 04:50 PMrectangle
Thank you so much.

I am such an idiot. - Oct 24th 2010, 04:57 PMArchie Meade
No, you are not.

You persisted. That's how to learn. Keep it up. - Oct 24th 2010, 09:37 PMUnknown008