b****y maths

Discussion in 'General Electronics Chat' started by dougal1111, Mar 23, 2011.

  1. dougal1111

    Thread Starter New Member

    Jan 12, 2011
    22
    0
    hi found this on a data sheet-
    1 / Freq. = 2 (0.694) x 470000 x 0.0000001 = 0.65236
    i,m a bit puzzled by the notation (0.694)

    i thought bracketed items comprise two figures to be calculated first.

    thank you
    dougal
     
  2. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
    141
    It's a common notation to denote multiplication and keep numbers separate. I use it a lot when writing down intermediate numerical calculations; for some reason, I prefer it over writing a binary operator like *. Why? Dunno -- that's the way I've done it most of my life...

    Multiplication over reals is associative, so there's no worry about ordering or precedence in the given expression.
     
  3. dougal1111

    Thread Starter New Member

    Jan 12, 2011
    22
    0
    thanks someonesdad ,at least they have'nt used powers of 10, that would have confused me. unless you know exactly what to do, its too easy to get the decimal point in the wrong place, and with multi-digit calculators now freely available,a little pointless,

    thanks again
    dougal
     
  4. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    No, writing numbers using powers of ten (scientific or exponential notation) is not pointless at all (and no pun intended). Actually, keeping track of the decimal point otherwise gets really difficult once you start dealing with some of the very large large quantities or very small ones used in electronics.

    For instance gigahertz, 1.×10^{9}Hz, pico-farads, 1.×10^{-12}F or the electron charge, −1.602×10^{-19}C. You would need one #ε&£ of a calculator display to cope with those, and before long you would lose count of all the little zeros.
     
  5. dougal1111

    Thread Starter New Member

    Jan 12, 2011
    22
    0
    thanks adjuster,anything over 10 decimal places is of course impractical using zeros , i stand corrected.

    regards
    dougl
     
  6. dougal1111

    Thread Starter New Member

    Jan 12, 2011
    22
    0
    just to clarify, the equation could (should?) have been written as -
    1 / Freq. = 2 x 0.694 x 470000 x 0.0000001 = 0.65236

    or indeed 1 / Freq. = 2 (0.694)( 470000)(0.0000001) = 0.65236

    thank you for bearing with someone to whom math/s does not come easily

    electronics must be a wonderful pathway to mathematics,

    thank you again

    dougal
     
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