P57
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Square Root Convergents

ℹ️Published on Friday, 21st November 2003, 06:00 pm; Solved by 45893;
Difficulty rating: 5%

It is possible to show that the square root of two can be expressed as an infinite continued fraction.

2=1+12+12+12+

By expanding this for the first four iterations, we get:

1+12=32=1.5
1+12+12=75=1.4
1+12+12+12=1712=1.41666
1+12+12+12+12=4129=1.41379

The next three expansions are 9970, 239169, and 577408, but the eighth expansion, 1393985, is the first example where the number of digits in the numerator exceeds the number of digits in the denominator.

In the first one-thousand expansions, how many fractions contain a numerator with more digits than the denominator?



Soluzione

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