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

You are not logged in.

## #1 Help Me ! » Inverse Function » 2014-05-15 02:44:56

DaveRobinsonUK1
Replies: 2

Hi All

I have come across this problem and it's giving me some jip.

I have a function

I would like to be able to put in the field of view and then solve for the focal length. Is this possible, what with
there being 2 internal variables?

David

## #2 Re: Euler Avenue » I'm looking for a quote about maths » 2012-01-22 07:27:20

I'm going to read my book again that has that quote in it. And then write to the author with a shaking fist. Homer Simpson style

Although it could be that I am reading from too many books and getting confused.

These are the people who treat maths as a religion. They are the people who just accepted that [math]I'm going to read my book again that has that quote in it. And then write to the author with a shaking fist. Homer Simpson style

## #3 Re: Help Me ! » Dual Variable Quadratic Solve » 2012-01-22 06:32:02

cool my man!

I can move on with this Universal Hyperbolic stuff now. Apparently .

## #4 Re: Euler Avenue » I'm looking for a quote about maths » 2012-01-21 22:07:06

'In mathematics, you don't understand things. You just get used to them.'

Richard Feynman??

## #5 Re: Help Me ! » Dual Variable Quadratic Solve » 2012-01-21 22:02:17

Hi Bobby

Sorry about the delay, been a hectic week here.

## #6 Re: Help Me ! » Dual Variable Quadratic Solve » 2012-01-17 20:38:13

Hi Bobby

Thanks for this.

I can follow it to there, and then i got this. Not sure if its cheating or not.

if i divide by

and then mult by -1 i get

and

if I divide by

i can get

which would be

i have done this by assuming that the rhs contains the empty set. Though I'm not sure
if that is valid.

## #7 Help Me ! » Dual Variable Quadratic Solve » 2012-01-17 09:20:12

DaveRobinsonUK1
Replies: 7

Hi Guys

I have a problem, I have spent so long (the last year or so) working on differentiating and integrating multivariable stuff that I have completely bypassed just being able to solve them. And now I need to be able to solve them. Bummer. I've had a go at the problem I have, though came unstuck and when I did some reading on the tinterweb its all confusing.

Here is the problem.

supposed to solve for r with the results given as

or

the closest i have come has been

All i have done to go further than this just doesn't go anywhere into being a

## #8 Re: Coder's Corner » Which software is better Maya or 3d max ? » 2011-12-01 22:48:44

Hi Bobby

It's excellent to be back.

I completely agree with you in needing maths more than ever. Without it there is only a certain amount you can do
with a computer. Making database/business programs is boring and certainly not why I got into computing.

## #9 Re: Coder's Corner » Programming Joke » 2011-12-01 22:36:37

Hi Bobby

I am calm now. Calm Calm Calm.

No I don't think they teach that anymore. I suppose with computers being so cheap and fast compared with what they
were, they must think it is not needed anymore. I prefer to work that way. It means I can lay on a couch with a pad,
pen and cup of tea. Just like Patrick Jane! Nice!

## #10 Re: Coder's Corner » MNEMONICS. » 2011-12-01 18:34:15

ganesh wrote:

I remember 3 mnemonics.

1. To determine the inauspicious time (Rahu kaalam) of the day as per Hindu religion. The inauspicious time lasts for 1 1/2 hours starting from 7.30-9AM.

Mother Saw Father Wearing The Turban on Sunday.

Monday-7.30-9AM, Saturday-9-10.30AM, Friday-10.30-12AM, Wednesday-12-1.30PM, Thursday-1.30-3 PM, Tuesday-3-4.30PM, Sunday-4.30-6PM.

2. Spectral class of stars

Oh Be A Fine Girl Kiss Me!

3. Color code in Resistors

B.B.ROY of Great Britain has a Very Good Wife.

Any more mnemonics???

For the resistor one my CT teacher at school taught us this

Bad Boys R*** Ordinary Young Girls But Virgins Go Without

Not exactly PC but this was the eighties, apparently it came out of BNFL, BAE Systems and Leyland Motors. Not sure if there is any
truth to that.

## #11 Re: Coder's Corner » Programming Joke » 2011-12-01 18:23:53

KrazyKyngeKorny wrote:

I knew a fellow, early twenties, who aspired to be a professional programmer.

He showed me some code for a program he was writing (BASIC).

At one point he had code like

if x < 10 then
if x < 8 then
(code)
else if x < 5 then
(code)

Unfortunately, much of this sort of thing goes on in professional programming.

Yeah! tell me about it. I work with artists who think because they have learned how write a small script
they are somehow equivalent to god. Not only do they do things like this, they also NEVER comment their
code. Then to add further complication they needlessly split functions out into separate files. Also they
don't document or provide test data for the program. As a result when you come to make some changes
you have to go through the whole thing line by line. They don't seem to understand the concept of making
it work on paper before going anywhere near a keyboard.

These people are a menace and have no business being in charge of a programming language.

## #12 Re: Coder's Corner » Which software is better Maya or 3d max ? » 2011-12-01 17:52:28

Bless me Bobbym for I have sinned! It has been months since my last post and my email account died and I had to start a new account on MIF.