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70's wiring in new sockets

Discussion in 'Electrics UK' started by sxturbo, 23 Jan 2021.

  1. SUNRAY

    SUNRAY

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    All very nice but I do have to ask the obvious question, how many times has anybody on here needed to work to more than 2 or 3 decimal places of π?
     
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  3. BS3036

    BS3036

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    I think you're missing the point!
     
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  4. SUNRAY

    SUNRAY

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    Which one, the 3rd or the 200th?
     
  5. JohnW2

    JohnW2

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    Fair enough. I once could produce 20 or 25 places 'without thinking', but I'm fairly impressed that, probably 50 years since I last had to make use of that, I managed to get the first 6 dp right :)

    'Back then', I could do similarly with "e", but these days I cannot confidently manage anything better than 2.7183.

    What worries me far more is that there are plenty of members of recent generators who resort to a calculator to replace their absent knowledge of even basic 'multiplication tables'!

    Kind Regards, John
     
  6. Harry Bloomfield

    Harry Bloomfield

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    Remembering them was something I was never good at, I was good at/ enjoyed the maths, but storing the tables - no. I tended to remember a few and calculate the rest. Thus - 3x7 = 21; 6x7 = 2x(3x7 =21) = 42. I would just remember a few landmarks and get the needed one by addition or subtraction. I was really glad when the early calculators came along in the early 70's.
     
  7. JohnW2

    JohnW2

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    'Remembering them' was essentially unavoidable for us. If I recall correctly, throughout my time at the 'infants' part of my primary school (age 5-7 years or thereabouts), every school day started with mass 'chanting' of the tables - so they came to be impressed on our memories in the same way as if we had learned, say, poems in the same way.

    Kind Regards, John
     
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  8. Harry Bloomfield

    Harry Bloomfield

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    The chanting, for the most part, just didn't work for me, so I had find good workarounds.
     
  9. JohnW2

    JohnW2

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    One of the problems with the 'chanting' method is that, at least for some people, it means that they have to mentally 'go through' the whole of a table' in order to get to the one they want.

    Fortunately, it's never been like that for me - I seem to be able to 'extract' just the bit I need from my memory - such that, say, if I want just "8 times nine" that one line of the 'poem' is all that I have to think about. However, other than for the 'most used' ones, I think that my mind does go through that "eight times nine equals..." though process before the answer 'jumps out' into my mind!

    Kind Regards, John
     
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  11. Captain Nemesis

    Captain Nemesis

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    That ones easier as it repeats to 8 places

    2.718281828
     
  12. Captain Nemesis

    Captain Nemesis

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    It wasnt.

    Zambia was bigger, but never got to much more than about 10% I think, and they found ways to continue to get a large amount of their production shipped through Rhodesia.

    That there was no significant price increase probably says it all.

    upload_2021-1-27_16-43-54.png
     
  13. JohnW2

    JohnW2

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    Sure, that's useful thing to remember if one only wants a maximum of 9 dps - but it doesn't help beyond that. To the first 50 dps ...

    2.71828182845904523536028747135266249775724709369995

    Kind Regards, John
     
  14. Captain Nemesis

    Captain Nemesis

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    Who needs even 9 places? My only point was about you saying you couldnt remember more than 4. Thought it was a useful tip that you only need to be able to remember to 5 and that the last 4 repeat.
     
  15. JohnW2

    JohnW2

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    Very few people, I imagine. Personally, I've rarely needed more than 4 - which is probably why that is all I can remember 'confidently'. In any event, for the past 40+ years, I haven't really needed to remember even one digit, since I've always had a calculator, or software, which enabled me to just 'press a button'!
    Yes, I was aware of the repetition of "1828".

    As you may know, a lot has been written about this over the centuries. Since the digits of e appear to be essentially random, the probability of any particular 4-digit sequence (such as "1818") occurring in any position is obviously 1 in 10,000. The probability of two occurrences of that sequence, consecutively, in the first 9 dps is therefore incredibly small, which has led a number of mathematicians to feel (almost certainly incorrectly!) that it "could not possibly just be a random happening" (i.e. could not just be a 'co-incidence'), so that they have sought (mathematical) 'explanations' - but, needless to say, none of them has ever found any 'explanation :)

    Kind Regards, John
     
  16. Captain Nemesis

    Captain Nemesis

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    Its entirely natural
     
  17. JohnW2

    JohnW2

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    People, even mathematicians, sometimes have difficulties in really believing that "random" means that "anything is possible", no matter how small the probability of that "anything"!

    Kind Regards, John
     
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