Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

You are not logged in.

## #1 Re: Help Me ! » Interesting Optics Problem » 2014-11-26 04:31:07

Thank you Bob for your assistance! All sorted now!

## #2 Help Me ! » Interesting Optics Problem » 2014-11-24 02:14:57

sulley
Replies: 4

Good Afternoon Everyone,

I have a problem that I was hoping you clever people may be able to help me with.

So, I am working on a camera focusing rig for a small camera module. The camera has a 42° FOV and the nominal focal distance required is 83mm. This is the distance along the centre line between the camera and a focus calibration image. This image is located on an inclined plane to provide 50mm of depth of field across the FOV. I am wanting to find the relationship between the focal distance and the length of the inclined plane and the angle required to maintain a DOF of 50mm

I have attached an image which will hopefully makes this easier to understand. This image has been knocked together in Visio, and I have used it to produce rough values for Theta and H, but it's very iterative and nasty, so I am trying to establish the formulae required to calculate angle theta and length H when I vary the focal distance. Regardless of how many triangles I draw on this image, I'm unable to progress.

Any help would be appreciated, any questions do let me know.

Regards,

Rob

## #3 Re: Help Me ! » Massive Numbers » 2012-12-05 05:26:53

I'm back again! Is that 92 in hex?

I have an even bigger challenge for you, would you be so kind as to calculate 141!^(162!^164!) for me please? to as large an accuracy as you dare! (ridiculous,  I know!)

Thanks,

Rob

## #4 Re: Help Me ! » Massive Numbers » 2012-11-28 02:36:44

bobbym wrote:

There is a math way but it is a bit complicated if you have never seen it before.
Are you interested?

Yes it would interest me, but realistically I will have very little use for the knowledge, so I won't take any more of your time.

bobbym wrote:

that's massive^massive. 10 or more years ago I went after the front digit of that number. I was a mere lad of only 82 years of age so I figured I would bring it to its knees before I died...

Doesn't that make you 92? Or am I missing something.

Thanks again for you help,

Rob

## #5 Re: Help Me ! » Massive Numbers » 2012-11-26 23:05:24

Wow, impressive! Thank you very much. Can you share how you did it please?

## #6 Help Me ! » Massive Numbers » 2012-11-26 22:26:01

sulley
Replies: 19

Hello all,

I was hoping you would be so kind as to help me with a problem that I'm having. I would like to calculate 141^(162^164), but the result is rather large and exceeds the capabilities of any software I have yet encountered.

I've tried using BC (see en.wikipedia.org/wiki/Bc_programming_language), you probably know that it's a very capable arbitrary precision calculator, but it can't manage it, it tells me that the 'exponent is too large in raise'.

Does anyone have any ideas? Do I have any chance of producing an actual result?

It's might be worth telling you that I know C, so can write some code to help, but the issue I have is that the types available in C aren't big enough, so I wouldn't even know where to start.

Thanks,

Rob