A fraction V in decimal form is an infinite string that comprises the non-repeat string v prefixing infinitely repeating period P of n digits. If the msd (the first digit) in P is #m^(th)# decimal digit, prove that V = v + #10^(-m) P/(1-10^(-n))#?
1 Answer
In the periodic part, with period P, the place value of the lsd (least
significant digit) =#10^(-m).
So, the value of the periodic part is
when
It follows that
Of course, this had been used in related problems that appeared
later.
Elucidation:
Let V = 2.1047 62705 62705 62705...
Here v= 2.1047, P= 62705, m = 9 and n = 5.
So,
This form is quite helpful in storing such values in the computer
memory, with zero truncation error.
After making an elusive correction 'least' for 'most', in this edition I
am confident now in suggesting this memory-oriented application.
What are to be stored are v, m, n and P, for no-loss,due to
truncation. In my opinion, this would sorely enhance precision in
computations involving simple fractions like
17/7 = ,2.428571 428571 428571...
The 10-sd value is 2.428571 429.
The exact value could be stored as
{v, m, n, P} = { 2, 6, 6, 428571 }